mB§ 

e 

^>>^*^^\^ 

m 

'J^f 

M 

\    / i 

ff^ 

%:■    '<\ 


-V^ 


^1-^; 


^^w 


•IM^^S^ 


Vf^K 


^;^^ 

:;  :^^ 

(■■  -• 

\ 

V. :  ■■■ 

■  // 

STUDIES  FR0I.;1  THE  PSYCHOLOGICAL  LABOR.\TORY 
OF  THE 
UKIVERSITY  OF  CALIFORIIIA 


REPRINTED  FROM 
THE'  PSYCHOLOGICAL  REVIEW 


LIBRARY 


EDUC. 

PSYCH. 

LIBRARY 


Ss^ 


CONTENTS 


Study 


I.     St rat ton,  George  ¥, 

A  new  determination  of  the  mirjimiim 
visible  and  its  bearing  on  locali- 
zation and  binocular  depth. 


TI. 


Dunlap,  Knight 


The  effect  of  imperceptible  shadows 
on, the  judgment  of. distance. 


III.     Stratton,  George  ¥, 

Visible  motion  and  the  space  thres- 
hold. 


IV.     Stratton,  George  M. 

The  method  of  serial  groups. 


V,     Nelson,  I:abel  Lorena. 

The  effect  of  subdivisions  on  the 
visual  estimate  of  time. 


VI.     Robe i-t son,  Alice. 

* Geometric -Optical'  illusions  in 
touch. 


VII. 


Brand,    Joseph  E. 

The  effect  of  verbal  suf^gesti 
upon  the  estimation  of  linear 
magnitudes. 


ons 


Manchester,  Genevieve  Savage. 

Experiments  on  the  unreflective 
ideas  of  men   and  women. 


M  3584 


-CONTEOTS 


Study 


IX,  Nelson,   Mabel   Lorena. 


The  difference   between  men  and  women 
in  the   recognition   of  color  and   the 
perception  of  sound. 


X.  Dunlap,    Knight. 

Extensity  and  pitclu 

XI.  Jones,   Grace  Mildred. 


Experiments   on  the   reproduction  of 
distance   as   influenced  by  suggestions 
of  ability  and  inability. 

XII.  Strong,   E.   K. 

The  effect  of  various  types  of  sugges- 
tion upon  muscular  activity. 

XIII.     Stratton,  George  M, 

The  localization  of  diasclerotic  light. 

XIV.     Brewer,  John  M. 


The   psychology   of  change:    On  some   phases 
of ^minimal  time  by   sight. 


XV.  Stratton,   George  M 


The   psychology  of  change: •   How  is  the 
percept; ion   of  movement   related  to  that 
of  succession? 


XVI.  Brown,   V\famer. 

Temporal  and  accentual  rhythm. 

XVII.  Stockton,   M.    I. 

Soitie   preferences   by  boys   and  girls   as 
shown  in  their  choice   of  words. 


REPRINTED    FROM 

VOL  VII.    No.  5.  September,  1900. 

THE 

Psychological  Review 

EDITED  BY 
J.  McKEEN  CATTELL  J.  MARK  BALDWIN 

AND 

Columbia  University  Princeton  Lnivbrsity 

ivith  the  co-operation  of 

ALFRED  BINET,  ficoLE  des  Hautes-£tudes,  Paris;  JOHN  DEWEY,  H.  H.  DONALD- 
SON, University  of  Chicago;  G.  S.  FULLERTON,  University  of  Pennsylvania; 
G.  H.  HOWISON,  University  of  California;  JOSEPH  JASTROW,  Uni- 
versity OF  Wisconsin;    G.  T.  LADD,  Yale   University;    HUGO 
MUNSTERBERG,  Harvard  University;  M.  ALLEN  STARR, 
College  of  Physicians  and  Surgeons,  New  York:  CARL 
STUMPF,  University,  Berun;   JAMES  SULLY, 
University  College,  Ixindon. 


STUDIES   FROM   THE   PSYCHOLOGICAL   LABORATORY 
OF   THE   UNIVERSITY   OF   CALIFORNIA. 

I.    A  New  Determination  of  the  Minimum  Visibile  and  its  Bearing 
ON  Localization  and  Binocular  Depth. 

BY   PROFESSOR   GEORGE   M.    STRATTON, 


II.    The  Effect  of  Imperceptible  Shadows  ox  the  Judgment 

OF  Distance. 

BY   KNIGHT   DUNLAP. 


PUBLISHBO   BI- monthly    BY 

THE  MACMILLAN  COMPANY, 

41  N.  QUEEN  ST.,  LANCASTER,  PA. 
66    FIFTH    AVENUE,    NEW   YORK. 


[Reprinted  from  The  Psychological  Review,  Vol.  VII.,  No.  S,  Sept.,  1900.] 


STUDIES    FROM   THE   PSYCHOLOGICAL  LABORA- 
TORY OF  THE  UNIVERSITY  OF  CALIFORNIA. 

I.    A  New  Determination  of    the  Minimum  Visible  and 
ITS  Bearing  on  Localization  and  Bin- 
ocular Depth. 

BY  professor  GEORGE  M.  STRATTON. 

The  smallest  lateral  difference  of  place  that  is  visible  has 
until  recently  been  given  as  about  5o''-6o''  angular  measure. 
The  method  employed  by  Helmholtz  and  others  ^  in  reaching 
this  result  was  the  well-known  one  of  bringing  two  parallel 
lines  together  until  they  finally  are  just  distinguished  as  two — 
on  the  same  general  principle  by  which  Weber  determined  the 
tactile  space-threshold,  by  finding  the  distance  between  two 
compass-points  that  just  cease  to  merge  into  one. 

But  by  a  different  method  it  is  now  evident  that  a  lateral 
difference  ^  of  place  of  about  7"  of  arc  can  be  directly  perceived. 

Instead  of  using  lines  or  points  side-by-side,  the  experi- 
ments which  give  this  result  were  made  with  lines  end-to-end, 
so  arranged  that  the  upper  of  two  perpendiculars  could  be 
moved  at  will  to  the  right  or  left  while  still  remaining  exactly 
parallel  to  the  lower  line,  as  shown  in  Fig.  i.  The  observer 
had  simply  to  judge  whether  the  upper  line  was  continuous 
with  the  lower,  or  to  which  side  it  had  been  displaced.  In  the 
initial  trials  the  lines  were  narrow  slits  of  light  surrounded  by 

'See  Helmholtz  :  Phystologische  Optik,  2d  ed.,  pp.  256  et  seq. 
*In  contrast  with  a  difference  in  depth  or  a  difference  not  of  itself  percep- 
tible, but  evident  merelj'  by  reason  of  stereoscopic  effect. 


Psjfchoiogical  Laboratof). 


ni'^,  .'':'./'  '::  ..i:'-^'?^ 


GEORGE   M.  STRATTON. 


a  black   ground — each  line  not  more  than   half    a  millimeter 
wide  and   some  lo  cm.  long,  and  observed  in  a  half-darkened 

room  from  a  distance  of  i8  meters. 
But  the  surprising  fineness  of  discrim- 
ination made  it  impossible  to  work 
with  accuracy  from  so  short  a  distance  ; 
so  that  finally  the  observer  was  placed 
120  meters  away,  and  the  lines  were 
changed  to  narrow  white  strips,  part 
of  the  time  lo  mm.,  part  of  the  time 
8  mm.,  wide,  each  50  cm.  long,  on  a 
dull-black  ground.  Each  line  with 
its  ground  was  mounted  on  the  face 
of  a  plate  of  glass,  the  two  glasses 
placed  edge  to  edge  in  a  frame ;  and, 
Fig.  I.  by  sliding  the  upper  plate   upon  the 

lower,  lateral  shifts  were  made  by  steps 
of  I  mm.  At  first  the  ordinary  procedure  of  '  minimal  changes  ' 
was  adopted,  but  it  soon  became  clear  that  suggestion  was  play- 
ing too  large  a  role,  and  resort  was  had  to  a  compromise  be- 
tween this  method  and  that  of  '  right-and-wrong  cases,'  which 
might  be  called  a  method  of  serial  groups,  to  be  described  more 
fully  at  another  time.  Taking  as  the  threshold  the  point  where 
8ofo,  or  more,  of  correct  judgments  occurred,  the  following  re- 
sults were  obtained  : 

Subject  A.    (187  judgments). 

Thresholds  for  Displacements  to  the 
Right.  Left. 


2.  mm. 
4-    " 
3-    '■ 
Aver.  3.  mm. 


General  average  4.1  mm. 


5.  mm. 

6.  " 

5-    " 
Aver.  5.3  mm. 


Subject  D.  (277  judgments). 

Thresholds  for  Displacements  to  the 
Right  Left. 


4.    mm. 

6.    mm 

3-      " 

2.       " 

5.  " 
5-       " 

ver.  3.2    "                                        Aver. 
General  average  4.2  mm 

5-  " 
5.2     " 

CALIFORNIA    PSYCHOLOGICAL    LABORATORY.  43 1 

Taking  i  mm.  as  equivalent,  approximately,  to  1.7  seconds 
of  arc,  where  the  radius  is  120  m.,  we  get  a  fraction  over  7  sec- 
onds as  the  threshold  of  space-distinction  under  these  conditions. 

The  experiments  were  begun  with  some  doubt  whether  there 
was  a  direct  perception  of  a  spatial  difference  here ;  whether, 
for  instance,  some  purely  intensive  change — some  apparent 
dimming  or  strengthening  of  the  impression  from  the  adjacent 
ends  of  the  lines  where  the  displacement  occurred — might  not 
serve  to  suggest  indirectly  a  spatial  inequality.  But  anyone 
making  the  observation  is  soon  convinced  that  what  he  sees  is 
not  of  this  character,  but  that  the  two  lines  seem  to  form  a 
single  line  no  longer  straight.  He  seems  to  compare  the  posi- 
tion of  one  of  the  lines  with  an  imaginary  extension  of  the 
other,  and  to  notice  that  the  two,  in  this  way,  do  not  coincide. 
As  a  check,  however,  the  observers  throughout  the  experiments 
were  kept  in  ignorance  of  the  actual  direction  of  the  displace- 
ments, and  the  threshold  was  not  considered  as  reached  until  the 
direction  could  be  told  by  them ;  so  that  if  their  judgments  had 
been  based  on  anything  other  than  the  perceptible  position  of  the 
lines,  the  fact  of  a  break  or  shift  in  general  might  perhaps  have 
been  inferred,  from  some  intensive  difference  in  the  light,  but  it 
is  difficult  to  see  how,  from  that  alone,  the  subjects  would  have 
been  able  to  tell  correctly  to  which  side  the  line  had  been  moved. 
There  seems,  moreover,  to  be  nothing  inherently  suspicious  in 
the  striking  disparity  between  these  results  and  those  obtained 
by  the  older  method.  In  the  threshold  obtained  in  Helmholtz's 
way  these  finer  measurements  are  not  reached  simply  because 
the  diffusion  of  the  stimulus  from  the  two  lines  side-by-side 
makes  a  fairly  uniform  blur  on  the  retina  between  them,  and 
within  the  limits  of  the  blur  two  separate  objects  can  no  longer 
be  [distinguished.  But  when  the  lines  are  arranged  as  in  the 
present  experiment,  any  such  interference  by  mere  diffusion  is 
greatly  lessened,  and  the  localities  can  be  clearly  and  correctly 
distinguished. 

The  result  thus  obtained  is  interesting  in  several  ways.  In 
the  first  place,  it^probably  removes  the  grounds  for  inferring, 
as  yet,  that  stereoscopic  depth  at  its  minimum  is  a  subconscious 
result  of  the  spatial  conflict  of  the  two  images.     M.y  own  ex- 


432  GEORGE   M.  STRATTON. 

periments  with  the  pseudoscope  *  had  shown  that  an  angular 
difference  of  24  seconds  between  the  two  impressions  was  suffi- 
cient to  give  a  binocular  relief.  Still  later,  Bourdon,^  experi- 
menting with  needles  at  short  range,  found  that  a  difference 
amounting  to  but  five  seconds  produces  a  perceptible  depth- 
effect.  As  long  as  the  conscious  lateral  threshold  was  counted 
as  above  60  seconds,  one  would  be  tempted  from  these  results 
to  believe  either  that  stereoscopic  depth  was  not  due  primaril}^ 
to  a  lateral  space-discrimination  of  the  two  images,  or  else  that 
the  plastic  effect  must  depend  on  a  subconscious  action,  since 
the  disparities  in  the  image  were  smaller  than  could  be  con- 
sciously noted.  The  present  reduction  of  the  conscious  lateral 
threshold  to  about  7  seconds  leaves  but  a  small  margin  upon 
which  to  base  such  conclusions,  particularly  when  one  takes 
into  account  the  wide  contrasts  in  the  (non-essential)  conditions 
of  the  experiments.  Bourdon  would  seem  entirely  justified, 
however,  in  concluding  that  binocular  depth  cannot  be  due  to 
our  detecting  double  images,  if  by  double  images  we  are  to 
understand  outlines  that  are  distinguishable  side-hy-side.  But 
the  depth-effect  may  still  be  due  to  the  presence  of  double  im- 
ages in  the  sense  of  outlines  that  are  felt  not  to  be  coincident 
when  positions  are  compared  end-to-end.  There  certainl}'-  is  a 
difficulty  in  that  ordinary  stereoscopic  vision  seems  hardly  to 
provide  the  conditions  for  comparing  outlines  in  this  way.  It 
is  barely  possible,  however,  that  the  curious  phenomenon  of 
retinal  rivalry  may  be  useful  just  herein,  that  by  the  successive 
emerging  and  disappearance  of  parts  of  the  outlines  in  the  two 
projected  fields  of  view  something  comparable  to  the  condi- 
tions of  the  present  experiment  is  brought  about,  and  an  ex- 
ceedingly fine  perception  of  lateral  incongruity  results. 

But  perhaps  a  more  important  bearing  of  the  experiment  is 
on  the  general  problem  of  visual  localization.  It  seems  highly 
improbable  that  so  minute  a  displacement  is  discerned  by  no- 
ting some  muscular  jog  or  unevenness  in  running  our  eyes  up 
and  down  the  line,  when  one  recalls  that  the  fovea  itself  is  some 

1 A  Mirror  Pseudoscope  and  the  Limit  of  Visible  Depth,  Psychological 
Review,  Vol.  V.,  p.  632. 

^L'acuite  stereoscopique,  Revue  P/tilosophique,  ]?in\.\3.ry,  1900. 


CALIFORNIA   PSYCHOLOGICAL   LABORATORY.  433 

300  times  broader  than  the  retinal  image  of  the  space-inequality 
here  perceptible.  In  view  of  this  relatively  wide  expanse  of 
the  fovea,  it  seems  highly  questionable  whether  the  eye,  in  run- 
ning up  and  down  such  a  pair  of  lines  would  regularly  take 
one  course  when  the  lines  exactly  met  and  a  perceptibly  different 
course  when  one  line  was  displaced  ^" .  The  eye  naturally 
moves  by  twitches  and  jerks,  even  when  following  a  straight 
line ;  the  breadth  of  the  fovea  is  such  as  to  permit  considerable 
roving  without  '  losing  '  the  line.  So  that  so  small  a  disloca- 
tion in  the  objective  line  would  probably  be  no  incentive  to  an 
exactly  corresponding  change  in  the  movement  of  the  eye. 
And  even  supposing  that  a  dislocation  of  *]"  in  one  of  the  lines 
did  regularly  tend  to  draw  the  eye  by  so  much  out  of  its  course  ; 
how  should  we  be  able  accurately  to  interpret  so  slight  a  varia- 
tion of  muscular  action,  as  clearly  due  to  an  objective  spatial 
inequality,  when  much  greater  movements — likewise  involun- 
tary, are  constantly  occurring  without  our  interpreting  them  as 
due  to  a  spatial  variation  in  the  object  we  are  observing? 

If,  on  the  other  hand,  we  pass  from  the  muscular  apparatus 
and  look  to  the  minute  elements  in  the  retina  to  explain  such 
discriminations,  even  these  seem  much  too  gross  to  account  for 
the  marvellous  fineness  of  our  judgment.  Rows  of  cones  in 
the  mosaic  of  the  fovea  lie  apart  a  distance  corresponding  to  at 
least  an  angular  measurement  of  3o'^  To  explain  our  power 
to  detect  a  spatial  difference  one-fourth  of  this,  it  will  be  neces- 
sary to  assume  either  that  the  rods  and  cones  are  not  the  ulti- 
mate spatial  elements  in  the  retina,  or  else  that  the  miinmum 
visible  may  be  considerably  less  than  the  distance  between  the 
center  of  the  adjacent  sensory  elements. 

And,  after  all,  it  is  not  difficult  to  see  how  this  latter  might 
well  be  the  case.  We  must,  however,  first  give  up  the  notion 
that  the  light,  even  when  it  falls  upon  a  single  cone,  or  row  of 
cones,  affects  only  those  elements  upon  which  it  directly  falls. 
In  every  case  the  stimulation  is  probably  diffused  in  all  direc- 
tions ;  a  responsive  wave  runs  through  the  neighboring  elements, 
as  is  evidenced,  for  instance,  by  the  fact  of  simultaneous  con- 
trast. Now  if  C  and  O  be  adjacent  elements,  and  b  the  boun- 
dary between  them,  then  it  seems  not  improbable  that  if  a  ray 


434 


GEORGE   M.  STRATTON. 


c 


Fig.  2. 


fall  somewhere  within  the  limits  of  C  its  effect  upon  O  will  be 
different  according  as  its  point  of  incidence  is  nearer  or  farther 
from  d.  It  would  probably  excite  O  more  intensely  the  nearer 
it  fell   to  the  limits  of  this  cone ;    and,  on  the  other  hand,  its 

effect  upon  O',  a  neighbor  on  the 
opposite  side  of  C,  would  cor- 
respondingly decline.  In  such 
an  event  there  would  be  a  differ- 
ence of  nervous  result  with  every 
change,  however  small,  of  the 
point  of  incidence,  instead  of  a 
change  occurring  only  in  case  the 
stimulus  passed  to  an  entirely  dif- 
ferent cone.  There  would  then 
be  a  difference  of  intensity  of  the 
diffusive  effect  upon  neighboring  elements,  a  different  degree  of 
whatever  kind  of  reaction  may  be  characteristic  of  each,  and  con- 
sequently a  change  of  '  local  sign '  even  when  the  difference  of 
place  of  the  excitation  is  considerably  less  than  the  diameter  of  a 
single  element.  The  local  signs  in  the  retina  alone,  quite  apart 
from  the  muscular  mechanism,  would  thus  form  an  absolutely 
continuous  series,  and  would  furnish  the  data  for  any  degree  of 
spatial  discrimination  we  may  discover.  The  retinal  sign  of  posi- 
tion is  thus  conceived,  not  often  the  analogy  of  our  electric  signal 
boxes,  when  one  unalterable  mark  is  given  (a  falling  numeral, 
for  example)  whenever  the  same  terminal  is  affected ;  but  we 
should  have  to  symbolize  it  rather  by  some  more  complicated 
contrivance  :  where  nothing  less  than  several  neighboring  num- 
bers dropped  on  each  occasion,  but  each  of  these  appeared  with 
differing  clearness  according  as  its  particular  terminal  was  near 
or  far  from  the  immediate  origin  of  the  disturbance.  The  rela- 
tion of  the  various  intensities  could  in  this  case  be  a  sign  both 
of  direction  and  of  distance ;  and  the  exact  seat  of  the  exciting 
cause  be  determined  with  a  degree  of  accuracy  depending  on 
the  fineness  of  discrimination  for  intensive  differences  and  for 
catching  their  interrelation,  rather  than  upon  the  number  and 
distance  apart  of  the  several  terminals ;  in  other  words,  the 
threshold  would  not  depend  on  the   purely  anatomical  meas- 


CALIFORNIA    PSYCHOLOGICAL    LABORATORY.  435 

urements,  if  we  may  drop  the  figure  and  return  to  the  retinal 
fact. 

The  present  experiment,  then,  tempts  one  to  believe  that  the 
local  signs  are  of  this  exceedingly  complicated  character.  The 
mental  process  of  localization,  or  of  space-distinction,  cannot 
be  justly  described  (it  would  seem)  as  an  association  merely 
between  a  particular  quality  of  sensation  and  a  particular  place. 
Nor  is  it  entirely  sufficient  to  amend  this  and  say  that  the  mind 
must  also  take  account  of  the  various  intensities  of  the  quality 
which  is  spatially  significant.  The  complication  seems  to  go 
still  a  degree  higher,  so  that  the  interrelation  of  numberless  in- 
tensities of  different  retinal  sensations  would  seem  to  be  the 
intricate  process  involved  in  even  the  simplest  visual  perception 
of  space.  When  we  bear  in  mind  that  the  fully  organized  per- 
ception without  doubt  includes  also  extra-retinal  data,  it  is  evi- 
dent how  complex  an  activity  our  spatial  consciousness  is. 


II.      The    Effect    of    Imperceptible    Shadows    on    the 
Judgment  of  Distance. 

BY  KNIGHT  DUNLAP. 

The  conscious  effect  of  stimulation  of  such  low  intensity 
as  to  be  imperceptible  presents  an  attractive  and  almost  unex- 
ploited  field  for  experimental  work.  The  experiments  of  Jas- 
trow  and  Pierce  on  small  differences  of  sensation,^  and  some 
previous  work  of  my  own,  suggested  the  possibility  of  obtain- 
ing important  results  from  an  experiment  planned  to  show 
directly  the  effects  of  the  presence  or  absence  of  an  impercep- 
tible stimulation. 

The  Miiller-Lyer  figure  was  selected  as  the  foundation  for 
such  an  experiment.  If  we  have  the  segments  of  the  principal 
line  in  the  illusion-figure  distinctly  marked,  but  the  angular 
lines  of  an  intensity  just  below  the  threshold  of  perception,  we 
have  the  simple  materials  for  determining  whether  or  not  these 
imperceptible  lines  will  produce  in  any  degree  the  ordinary 
illusion-effect.     If  such  an  effect  is  produced,  then  we  have 

1  Memoirs  of  the  National  Academy  of  Sciences,  Vol.  III.,  p.  76. 


436 


KNIGHT  DUN  LAP. 


evidence  for  the  belief  that  under  certain  conditions  things  of 
which  we  are  not,  and  can  not  become,  conscious  have  their  im- 
mediate effects  upon  consciousness. 

The  apparatus  used  in  the  first  investigations  under  these 
conditions  was  very  simple,  and  not  altogether  satisfactory  in 
its  operation,  but  as  the  experiments  were  of  the  nature  of  a 
preliminary  survey  of  the  ground,  it  was  not  deemed  advisable 
to  make  a  complicated  arrangement  of  apparatus. 


Fic 


Fig.  2. 


The  screen  upon  which  the  illusion-figure  vv^as  to  be  shown 
was  a  sheet  of  white  bristol-board,  fifty-eight  centimeters  by 
seventy-two  centimeters,  fastened  upon  a  frame.  A  black  line 
one  millimeter  in  width  (see  Fig.  i)  was  drawn  across  the  mid- 
dle of  the  screen  horizontally,  and  divided  in  the  center  by  a 
perpendicular  line  three-fourths  of  a  millimeter  in  width,  and 
extending  eight  millimeters  on  each  side.  On  the  sides  of  the 
frame  holding  the  screen,  and  on  a  level  with  the  horizontal 
line  were  fixed  guides,  in  which  slid  small  steel  rods  passing 
along  the  line  and  hidden  against  it.  Small  strips  of  black 
paper  two  millimeters  wide  and  ten  millimeters  long  were  fas- 
tened to  the  inner  ends  of  these  rods  in  positions  parallel  to  the 
central  vertical  line  and  extending  equally  above  and  below  the 
horizontal  line,  and  these  with  the  central  vertical  line  marked 
off  two  segments  of  the  horizontal  line.  The  lengths  of  these 
segments  could  be  varied  at  will  by  sliding  the  rods  along  the 
horizontal  line. 

Fastened  to  each  of  these  rods  carrying  strips,  and  parallel  to 
them,  was  another  exactly  similar  rod  passing  behind  the  screen 
and  bearing  on  its  inner  extremity  an  angle  of  ninety  degrees, 
cut  from  black  bristol-board,  with  legs  five  millimeters  wide  and 


CALIFORNIA   PSYCHOLOGICAL    LABORATORY.  437 

forty-five  millimeters  long.  These  angles,  together  with  a  simi- 
lar one  fastened  in  the  center,  showed  upon  the  front  of  the 
screen  as  shadows  when  light  was  transmitted  through  from  the 
back,  and  transformed  the  segments  of  the  line  into  the  typical 
Miiller-Lyer  figure.  The  arrangement  of  this  part  of  the 
apparatus  maybe  understoood  from  Figs,  i  and  2,  which  show 
respectively  the  front  and  back  of  the  screen.  It  will  be  ob- 
served that  by  interchanging  the  pairs  of  rods  and  reversing  the 
central  angle  the  direction  of  the  illusion  could  be  reversed. 

The  screen  was  illuminated  from  the  front  by  two  hooded 
incandescent  lights  placed  one  at  each  side  so  as  not  to  obstruct 
the  view,  and  at  equal  distances  from  the  screen.  Behind  the 
screen  w^as  a  single  hooded  incandescent  light,  so  shielded  with 
tissue  paper  as  to  diffuse  the  light  as  evenly  as  possible  over  the 
back  of  the  screen.  The  intensity  of  this  light,  and  therefore 
the  intensity  of  the  shadows  on  the  front  of  the  screen,  was  con- 
trolled by  means  of  a  rheostat,  the  front  lights  remaining  un- 
changed. As  the  current  for  the  three  lights  vv^as  taken  from 
the  same  circuit,  variation  in  the  potential  affected  them  all  in 
approximately  the  same  ratio,  and  hence  the  relative  intensit}* 
of  the  light  coming  through  the  screen  to  the  light  falling  upon 
the  face  of  it,  as  determined  b}^  the  adjustment  of  the  rheostat, 
might  be  supposed  to  remain  fairly  constant. 

The  method  of  operation  was  very  simple.  One  of  two  fig- 
ures, a  double  square  and  a  circle,  was  placed  against  the  back 
of  the  screen  to  test  the  intensity  of  the  light,  and  the  intensity 
of  the  rear  light  w^as  reduced  until  the  subject  was  unable  to  de- 
tect the  shadows  caused  by  the  figure.  Upon  reaching  a  point 
at  which  it  was  certain  that  the  subject  could  not  tell  whether 
the  figure  was  circular  or  square,  it  w^as  removed  and  the  an- 
gles of  the  Miiller-Lyer  figure  placed  in  position.  It  was  de- 
termined by  the  toss  of  a  coin  whether  the  angles  should  be  set 
in  the  '  short '  or  '  long  '  position,^  and  the  left  cross-line  was 
fixed  at  twenty-five  centimeters   from   the  center.     The   right 

iThe  direction  of  the  angles  which  tends  to  shorten  the  left  or  standard  seg- 
ment of  the  line,  thus  <:^ — ^ <  ,  will,  throughout,  be  spoken  of  as  '  illu- 
sion short.'  The  opposite  direction  of  the  angles,  which  tends  to  lengthen  the 
left  segment,  will  be  spoken  of  as  '  illvision  long.' 


43S  KNIGHT  DUN  LAP. 

cross-line  was  started  from  a  point  sufficiently  greater  or  less 
than  twenty-five  centimeters  from  the  center  to  be  distinctly  per- 
ceived as  farther  or  nearer  than  the  left  one,  and  moved  at  reg- 
ularly timed  intervals^  by  steps  of  one  millimeter  towards  and 
past  the  equality  point,  the  judgment  of  the  subject  as  to  the 
length  of  the  right  segment  of  the  line  as  compared  with  the 
left  segment  being  recorded  at  every  step  in  the  series. 
Whether  the  cross-line  should  move  inward  from  a  point  be- 
yond the  equality  point,  or  outward  from  a  point  inside,  was 
determined  by  lot,  correction  being  made  toward  the  close, 
however,  so  as  to  have  on  the  whole  as  many  series  of  one  kind 
as  of  the  other  in  order  to  offset  the  effect  of  mere  direction  of 
motion.  It  is  evident  from  the  details  given  above  that  the  angle 
behind  the  right  cross-line  moved  with  it,  so  that  the  relations 
of  the  Miiller-Lyer  figure  were  constantly  preserved. 

Series  of  this  kind  alone  would  of  course  not  be  sufficient  to 
determine  whether  or  not  the  illusion  figure  is  effective.  As 
will  be  seen  later,  there  is  a  tendency  to  judge  the  equal  seg- 
ments of  a  line  as  different  even  apart  from  any  influence  of  the 
angles  of  the  Miiller-Lyer  figure.  Hence  it  was  necessary  for 
purposes  of  comparison  with  these  to  take  also  series  in  which 
there  could  be  no  possible  illusion,  since  the  light  behind  the 
screen  was  entirely  cut  off.  If  there  should  be  any  effect  pro- 
duced by  the  shadows  under  the  conditions  previously  stated, 
a  comparison  of  the  series  with  those  taken  when  the  shadows 
of  the  angles  were  present  but  imperceptible  might  show  it. 

The  series  were  consequently  taken  in  pairs  or  sets,  each 
pair  being  composed  of  one  series  with  the  shadows,  and  one 
without,  taken  in  immediate  succession,  in  the  same  direction, 
and  from  the  same  point.  The  order  in  which  the  two  were 
taken  was  determined  for  each  pair  by  lot,  as  was  also  the  direc- 
tion of  the  illusion  as  mentioned  above.  The  subject  being  ig- 
norant of  the  results  of  the  lots,  there  was  a  double  check  upon 
the  possibility  of  any  influence  arising  from  his  knowledge  of 
how  the  illusion  might  be  expected  to  affect  his  judgments. 
Any  general  difference  between  the  two  classes  of  series  could 

iThe  interval  was  nine  seconds  in  length  from  the  completion  of  a  judgment 
until  the  command  to  look  again  at  the  screen. 


CALIFORNIA    PSYCHOLOGICAL    LABORATORY. 


439 


therefore  only  be  due  to  the  effect  of  the  angles  behind  the 
screen. 

In  general,  each  series  proceeding  outward  resulted  in  first 
a  number  of  judgments  of  '  shorter,'  then  one  or  more  of 
'  equal '  or  '  doubtful,'  and  finally,  a  number  of  '  longer.' 
In  the  series  proceeding  inward  the  order  was  reversed.  The 
middle  point  of  the  region  of  doubt  and  equality  was  taken  as 
the  mean  equality  point  of  each  series,  and  this  was  compared 
with  the  mean  equality  point  of  the  other  member  of  the  pair. 
The  region  of  doubt  and  equality  was  determined  by  fixed  rules, 
and,  in  order  to  secure  absolute  impartiality  the  point  was  de- 
termined without  the  experimenter  himself  knowing  to  which 
class  the  series  belonged.  For  this  purpose  a  number  of  the 
records  were  allowed  to  accumulate,  were  shuffled,  and  their 
distinctive  marks  concealed  until  their  mean  equality  points 
were  determined  and  recorded. 

Three  subjects  were  employed,  and  the  results  of  the  work 
with  them  are  summed  up  in  Table  I.  A  set  was  counted  '  for  ' 
or  '  against '  the  illusion  according  as  the  difference  between 
the  mean  equality  points  of  the  two  series  composing  it  was  or 
was  not  in  the  direction  which  would  correspond  to  the  possible 
effect  of  the  illusion-figure. 

Table  I. 


Subject. 

Total  Pairs. 

For  Illusion. 

Against. 

Neutral. 

A. 

R. 

S. 

23 

II 

13 

14 
9 

8 

8 

2 

5 

I 
0 
0 

We  see  from  this  table  that  60  per  cent,  of  the  sets  for  sub- 
ject A.  fall  on  the  side  of  the  illusion,  81.8  per  cent,  for  R., 
and  61.5  per  cent,  for  S.  The  figures  are  rather  meager,  but 
as  far  as  they  go  are  strongly  suggestive.  As  the  experiments 
were  designed  only  as  preparatory  to  the  investigation  proper, 
to  point  to  possible  results  and  expose  the  difficulties  in  the  way, 
the  results  were  counted  sufficient,  and  preparations  were  made 
for  more  careful  experiments  along  the  same  line. 

The  apparatus  used  in  the  later  work  differed  materially 
from  that  which  was  described  above  in  the  account  of  the  pre- 


440 


KNIGHT  DUN  LAP. 


liminary  investigation.  It  was  desired  that  there  should  be 
some  means  of  measuring  the  relative  intensities  of  the  shadows, 
and  as  this  was  practically  impossible  when  they  were  cast  by 
light  transmitted  through  the  screen,  it  was  decided  to  try  the 
effect  of  casting  the  shadows  directly  upon  the  front  of  the 
screen.  This  of  course  necessitated  the  removal  of  the  angles 
used  in  casting  the  shadows  to  some  distance  from  the  screen, 
in  order  that  they  might  not  be  in  the  subject's  line  of  vision, 
and  this  in  turn  demanded  the  use  of  light  radiating  from  a 
very  small  area,  that  the  shadows  might  be  sharply  defined. 
The  best  form  of  illumination  available  for  this  purpose  was 
the  electric  arc,  and  as  it  is  not  possible  to  maintain  the  intensities 
of  two  arc  lights  at  anything  like  a  constant  ratio,  it  was  nec- 
essary to  cast  the  shadows  from  the  same  source  of  light  which 
furnished  the  general  illumination  of  the  screen.  This  was 
effected  by  the  aid  of  mirrors,  which  diverted  in  opposite  direc- 
tions the  light  coming  from  the  lamp,  and  combined  it  again 
upon  the  screen.     An  automatic  adjustment  lamp  was  first  tried  ; 


0V 


Fig.  3. 

but  as  it  proved  too  unsteady,  a  hand  adjustment  lamp,  with 
carbons  at  right  angles  to  each  other,  was  constructed  in  the 
laboratory  and  found  more  satisfactory.  The  arrangement  of 
the  lamp  with  the  other  parts  of  the  apparatus  is  shown  by  the 
diagram  in  Fig.  3.  The  lamp  was  placed  in  a  box  having  a 
blackened  interior  and  suitable  apertures  for  the  emission  of 
light  from  the  front,  and  for  ventilation.  The  light  reflected 
by  mirrors  N  and  M  fell  upon  the  screen  P  without  interven- 


CALIFORNIA    PSYCHOLOGICAL   LABORATORY.  441 

tion,  but  that  reflected  by  N'  and  M'  was  intercepted  by  the 
episkotister  E^  by  which  any  desired  proportion  of  the  light 
was  cut  out.  This  light  passed  through  the  frame  F,  in  which 
were  suspended  on  silk  fibers  angles  measuring  sixty  degrees 
(these  being  more  favorable  to  the  illusion  effect  than  those  of 
ninety  degrees  used  in  the  preliminary  work),  and  cast  their 
shadows  on  the  screen  P.  This  screen  was  the  one  used  in  the 
preliminary  work,  with  the  exxeption  of  the  angles  at  the  back, 
which  were  superfluous  in  the  present  arrangement,  and  were 
therefore  removed.  It  was  placed  in  a  position  perpendicular 
to  the  line  of  vision  of  the  subject  at  S^  who  was  seated  at  one 
side,  out  of  the  path  of  the  light,  and  hence  the  distribution  of 
the  light  on  the  face  of  the  screen  was  slightly  unsymmetrical. 
This  was  unavoidable,  however,  on  account  of  the  dimensions 
of  the  room  which  was  selected  as  best  adapted  to  the  purposes  of 
the  experiment.  The  walls,  floor  and  ceiling  of  the  room  were 
black,  preventing  any  great  reflection  of  light  back  to  the  screen. 

Some  difficulty  was  experienced  with  the  mirrors,  and  those 
of  carefully  selected  plate-glass  used  in  the  experiment  were 
not  thoroughly  satisfactory.  Better  results  could  probably  have 
been  obtained  by  the  use  of  lenses  and  totally  reflecting  prisms. 

The  fibers  by  which  the  angle  casting  the  right-hand  shadow 
was  suspended  were  attached  to  slides  working  in  the  frame  F^ 
so  that  the  angle  could  be  moved  along  as  the  right-hand  cross- 
line  was  moved  on  the  screen,  thus  keeping  the  vertex  of  the 
shadow  approximately  on  the  cross-line  on  the  screen  P.  The 
principal  remaining  pieces  of  apparatus  were  screens,  one  at 
R  to  prevent  the  subject  seeing  the  figure  at  P  except  at  the 
proper  time ;  and  one  at  T  to  conceal  the  angles  in  the  frame 
F  2X  all  times.  The  distance  from  the  subject  to  the  figure  was 
about  two  and  a  quarter  meters. 

It  will  be  observed  that  since  the  two  pencils  of  light  were 
taken  from  practically  the  same  side  of  the  glowing  carbon,  the 
effective  area  of  which  was  only  a  few  millimeters  in  extent, 
variations  in  the  intensity  of  the  light  affected  them  both  ap- 
proximately equally  as  regards  their  initial  intensities,  and 
hence  did  not  change  the  relative  intensities  as  established  by 
the  episkotister.     Since  therefore  the  intensity  of  the  light  did 


442  KNIGHT  DUN  LAP. 

not  vary  greatly,  the  perceptibility  of  the  shadows  should  have 
remained  constant  according  to  the  general  statement  of 
Weber's  law. 

What  has  been  said  concerning  methods  in  the  preliminar}- 
work  will,  with  some  important  exceptions,  apply  to  the  main 
work  also.  The  proper  intensity  of  the  shadows  was  deter- 
mined for  each  subject  by  careful  tests,  and  these  were  fre- 
quently repeated  during^the  course  of  the  experiment  to  insure 
the  correctness  of  the  mtensity  adopted.  It  was  found  that 
subjects  A.,  R.  and  W.  could  not  detect  any  shadows  when  the 
total  angular  opening  in  the  episkotister  was  seven  degrees. 
For  the  sake  of  safety  six  degrees  was  used  in  the  actual  work 
with  these  subjects.  S.  at  one  time  seemed  to  perceive  the 
shadows  with  an  aperture  of  seven  degrees,  and  therefore  five 
degrees  was  fixed  upon  as  entirely  safe  for  him.  These  pro- 
portions are  rather  large  as  compared  with  the  figures  usually 
given  for  the  difference-threshold  of  light,  but  it  should  be  re- 
membered that  the  shadows  were  not  perfectly  distinct,  on  ac- 
count of  the  effect  of  the  fringe  of  luminosity  surrounding  the 
effective  portion  of  the  positive  carbon,  and  also  on  account  of 
multiple  reflection  in  the  mirrors. 

As  it  took  some  time  to  change  the  direction  of  the  angles  in 
the  frame,  they  were  placed  at  the  beginning  of  each  experi- 
ment-period in  the  direction  determined  by  lot,  and  continued 
in  the  same  direction  during  the  whole  period  (three-quarters  of 
an  hour),  unless  (as  happened  some  few  times)  the  subject  ac- 
cidentally became  aware  of  the  direction  of  the  angles.  In 
such  a  case  a  coin  was  tossed  to  determine  whether  or  not  the 
angles  should  be  reversed,  the  subject  being  ignorant  of  the 
outcome  of  the  lot,  and  so  not  knowing  whether  the  shadows 
were  continued  in  the  position  in  which  he  saw  them,  or  were 
reversed,  or  were  entirely  removed  and  a  shadowless  series 
commenced.  Towards  the  end  of  the  work  the  angles  were 
arbitrarily  placed  so  as  to  have  an  equal  number  of  series  for 
each  of  the  two  directions  of  the  illusion.  To  economize  time, 
the  angle  which  cast  the  right  shadow  was  not  moved  each  time 
the  corresponding  cross-line  was  moved,  but  only  every  fifth 
time,  the  width  of  the  shadow  allowing  that  amount  of  move- 
ment without  complete  disconnection. 


CALIFORNIA    PSYCHOLOGICAL   LABORATORY. 


443 


No  attempt  was  made  to  run  series  in  both  directions,  as  it 
was  not  indispensable  for  the  comparison  of  the  series,  and 
there  were  enough  complications  without  this  additional  factor. 
All  the  series  were  run  outward  from  a  point  nearer  to  the  cen- 
ter than  the  standard  length  of  twenty-five  centimeters. 

When  the  shadows  were  removed,  in  the  shadowless  series, 
by  cutting  off  the  light  normally  reflected  by  mirrors  M'  and  N' , 
the  episkotister  was  kept  running,  and  the  angle  was  moved  in 
the  frame  at  the  usual  times  in  these  series  as  in  the  others,  so 
that  the  subject  had  no  clue  as  to  whether  or  not  the  shadows 
were  present  in  any  series. 

For  fear  lest  the  imperfections  in  the  mirrors  might  produce 
irregular  distribution  of  the  light  on  the  screen  in  such  a  way 
as  to  affect  the  results  of  the  series,  the  two  mirrors  on  one  side 
were  interchanged  from  time  to  time  with  those  on  the  other 
side,  and  an  equal  number  of  series  taken  in  each  of  the  two 
positions.  There  were  thus  three  conditions  to  be  equalized, 
viz  :  (i)  Position  of  the  mirrors  ;  (2)  Direction  of  the  illusion ; 
(3)  Order  of  series  in  the  set,  /.  ^.,  whether  the  series  with  the 
shadows  was  given  first,  immediately  succeeded  by  the  series 
without  the  shadows,  or  vice  versa;  in  the  scheme  which  fol- 
lows the  first  class  are  called  '  shadows  first '  and  the  second 
'  shadows  last.' 

This  classification  broke  the  sets  of  series  up  into  eight 
groups,  which  were  kept  equal  in  the  long  run  (with  one  ex- 
ception, to  be  mentioned  later),  although  the  sets  into  which 
the  series  fell  were  determined  by  lot  from  day  to  day  as  far  as 
possible.  These  groups  are  given  schematically  in  the  follow- 
ing table  : 


1st  position  of  mirrors. 


2d  position  of  mirrors. 


Illusion  long. 


Illusion  short. 


Illusion  long. 


Illusion  short. 


Shadows  first. 
Shadows  last. 
Shadows  first. 
Shadows  last. 
Shadows  first. 
Shadows  last. 
Shadows  first. 
Shadows  last. 


444  KNIGHT  DUN  LAP. 

On  account  of  the  complication  of  the  apparatus  and  the 
difficuhies  of  its  operation,  the  progress  of  the  experiment  was 
necessarily  slow.  No  attempt  was  made  to  have  the  subject 
judge  at  regularly  timed  intervals.  An  endeavor  was  made, 
however,  to  give  all  series  with  the  same  approximate  rapidity, 
and  the  rate  of  ten  minutes  to  a  set  was  pretty  constantly  main- 
tained. This  allowed  the  taking  of  three  sets  or  pairs  in  a 
period  of  forty-five  minutes,  if  all  worked  smoothly,  the  rest 
of  the  time  being  consumed  in  the  necessary  adjustments  of  the 
apparatus.  Very  frequently,  however,  troublesome  delays  oc- 
curred, which  reduced  the  number  of  sets  to  two  or  one. 

Each  subject  was  instructed  to  preserve  a  fixed  method  of 
bringing  his  eyes  upon  the  line.  One  preferred  to  bring  his 
eyes  upward  from  the  floor  to  the  middle  of  the  line  after  remov- 
ing the  swinging  screen,  while  the  others  preferred  to  gaze  at 
the  swinging  screen,  in  the  direction  of  the  center  of  the  line, 
and  then  displace  it.  This  regularity  was  insisted  upon  because 
it  was  found  by  actual  trial  that  the  direction  in  which  the  eyes 
were  brought  upon  the  screen  influenced  the  proportional  esti- 
mate of  the  segments  of  the  line.  Therefore  a  difference  in  this 
respect  between  the  different  series  might  introduce  a  difference 
in  the  results  which  would  confuse  the  interpretation. 

The  subject  was  not  however  compelled  to  maintain  his  gaze 
fixed  upon  the  central  point,  but  moved  his  eyes  over  the  line 
as  he  pleased  in  forming  his  judgment.  In  the  extreme  cases 
the  disparity  of  the  segments  of  the  line  was  perceived  by 
glancing  at  the  center,  but  where  the  difference  was  very  slight 
the  subject  gazed  at  one  segment  until  he  had  its  length  well 
in  mind  and  then  transferred  his  regard  to  the  other  segment  in 
order  to  make  comparison. 

It  is  probable,  however,  that  the  steady  fixation  of  the  seg- 
ments was  on  the  whole  a  bad  practice,  as  it  rendered  possible 
the  formation  of  an  after-image  of  the  first  segment  by  which 
the  second  segment  might  be  judged  by  mere  superposition,  which 
would  be  in  a  large  measure  destructive  of  the  effect  of  the  il- 
lusion, if  there  were  any  such  effect.  The  difficulties  of  judg- 
ing were  however  so  great  that  it  was  not  deemed  advisable  to 
place  any  additional  restrictions  on  the  subject. 


CALIFORNIA    PSYCHOLOGICAL    LABORATORY.  445 

The  experiment  would  naturally  have  been  much  simplified 
if  the  shadowless  series  had  been  omitted,  and  the  sets  of  two 
made  to  consist  of  one  with  the  illusion  short  and  one  with  it 
long.  This  would  have  reduced  the  number  of  groups  to  four, 
and  would  perhaps  have  nearly  doubled  the  difference  between 
the  series  on  each  set,  but  it  was  deemed  inadvisable  for  several 
reasons.  First,  the  changing  of  the  direction  of  the  angles  for 
each  series  would  have  consumed  so  much  time  that  the  gain  by 
omitting  the  shadowless  series  would  have  been  largely  offset. 
Second,  the  data  for  the  judgments  of  the  segments  of  the  line 
with  the  influence  of  the  illusion  excluded  are  important  in 
themselves.  And  third,  it  was  considered  possible  that  under 
the  conditions,  the  illusion,  if  effective  at  all,  might  be  more 
effective  in  one  position  or  direction  than  in  the  other ;  a  state 
of  affairs  of  which  the  proposed  method  would  offer  no  evi- 
dence, should  it  actually  exist.  The  results  as  set  forth  later 
justif}^  the  procedure  actually  adopted,  although  additional  ex- 
periments ought  to  be  made  in  the  proposed  manner  to  supple- 
ment the  results  of  these. 

One  more  point  as  to  the  methods,  and  then  we  may  pass  on 
to  the  next  division  of  the  subject.  The  series  were  always 
commenced  far  enough  inside  of  the  actual  equality-point  to 
give  a  distinct  impression  of  shortness  to  the  right  segment  of 
the  line.  They  were  not  however  commenced  uniformly  at  the 
same  point,  but  were  varied  irregularly^  in  this  respect  from  set 
to  set,  and  the  subject  was  given  to  understand  that  they  were 
irregular,  lest  the  distribution  of  his  judgments  in  one  series 
should  influence  him  in  the  next.  Both  of  the  two  series  of 
each  set  were  of  course  commenced  at  the  same  point,  so  that 
any  possible  effect  of  the  length  of  the  series,  or  the  strength 
of  the  contrast  with  which  the  series  began,  might  affect  them 
both  alike ;  but  this  was  not  mentioned  to  the  subject,  who  con- 
sequently never  knew  whether  a  given  series  began  at  the  same 
point  as  the  preceding.  It  is  interesting  to  note  that  the  gen- 
eral region  of  commencing  the  series  was  necessarily  varied 
from  day  to  day  and  even  from  set  to  set  on  account  of  the 
varying  relative  estimation  of  the  segments  of  the  line.  Thus 
a  point  which  one  day  was  well  within  the  range  of  judgments 


446 


KNIGHT  DUN  LAP. 


of  '  short '  might  be  the  next  day  within  the  range  of  judgments 
of  '  equal.'  This  will  be  further  exemplified  later  in  the 
discussion. 

Four  subjects  were  employed,  three  of  whom,  S.,  R.  and  A., 
had  taken  part  in  the  preliminary  work.  In  the  cases  of  S.  and 
R.  eighty  series  (forty  sets)  were  taken  from  each,  evenly  dis- 
tributed according  to  the  scheme  of  the  eight  classes  of  sets  al- 
ready specified ;  but  in  the  case  of  A.  only  sixty-four  series 
(thirty-two  sets)  evenly  distributed,  and  in  the  case  of  the  other 
subject,  W.,  seventy-two  series  (thirty-six  sets,  twenty  under 
the  class  'long'  and  sixteen  under  the  class  '  short')  were  ob- 
tained. 

The  most  obvious  method  of  comparison  of  the  series  was 
by  sets,  taken  in  the  same  manner  as  that  in  which  the  series 
in  the  preliminary  work  were  compared.  The  same  precautions 
for  impartiality  in  computation  were  observed  here  also.  The 
results  of  this  comparison  as  given  in  Table  II.  are  far  more 
striking  than  the  results  for  the  preliminary  work. 

Table  II. 


Subject. 

Total  Sets. 

For. 

Against. 

Neutral. 

S. 

40 

23 

15 

2 

W. 

36 

19 

II 

6 

R. 

40 

25 

9 

6 

A. 

32 

23 

7 

3 

Expressed  in  percentages  this  table  becomes  Table  III.,  as 

follows  : 

Table  III. 


Subject. 

f»  for. 

f  against. 

f  neutral. 

s. 

57-5 

37-5 

5-0 

w. 

52.8 

30.5 

16.7 

R. 

62.5 

22.5 

15.0 

A. 

68.8 

21.9 

9-3 

This  shows  a  preponderance  for  the  illusion ;  twenty  per 
cent,  for  S.,  over  thirty-two  per  cent,  for  W.,  forty  per  cent, 
for  R.  and  over  forty-six  per  cent,  for  A.  Or,  if  we  leave  out 
of  account  the  neutral  cases  and  give  directly  the  ratio  of  favor- 
able to  unfavorable  cases,  we  find  the  following  values  :  S.,  1.5. 


CALIFORNIA   PSYCHOLOGICAL   LABORATORY.  447 

W.,  1.7;  R.,  2.8,  and  A.,  3.1,  which  are  certainl}^  too  large 
and  agree  too  well  to  be  set  down  as  the  result  of  mere  chance. 
A  second  comparison  naturally  suggested  would  be  between 
the  average  of  the  mean  equality-points  for  the  shadowless  series 
and  the  averages  for  the  series  with  the  illusion-figure  in  both 
positions.  An  examination  of  the  series,  however,  showed  that 
the  average  for  all  of  the  shadowless  series  could  not  be  fairly 
compared  with  the  averages  for  each  of  the  other  two  classes, 
since  the  series  for  the  two  latter  occurred  in  groups  irregularly 
distributed  throughout  the  time  the  experiment  was  continued, 
and  the  general  position  of  the  mean  equality-point  varied 
greatly  during  the  progress  of  the  work. 


XN    / 


/  s  10  is  zo  zs  30  3s; 

Fig.   4. 

This  is  illustrated  by  Fig.  4,  which  gives  the  position  of  the 
mean  apparent  equality-points  for  each  of  the  shadowless  series 
of  experiments  with  subject  W.  In  this  diagram  the  values  of 
the  abscissa  represent  the  order  of  the  series  in  the  course  of  the 
experiment,  while  the  ordinates  give  the  difference  in  millimeters 
between  the  standard  line  and  that  length  of  the  variable  which 
seemed  equal  to  it.  Positive  ordinates,  therefore,  show  that  the 
apparently  equal  variable  was  actually  longer  than  the  standard, 
while  negative  ordinates  indicate  that  it  was  shorter. 

All  of  the  graphs  thus  obtained  were  ver}'  irregular,  and  those 
for  subjects  W.,  R.  and  A.  show  a  decided  upward  tendency 
from  first  to  last,  indicating  that  while  early  in  the  experiment 
the  right  segment  was   proportionately  overestimated,   later  it 


+fS 


KNIGHT   DUNLAP. 


was  underestimated.  Subject  S.,  with  a  single  exception,  over- 
estimated the  right  segment  throughout  the  experiment,  rather 
more  toward  the  last  than  the  rirst. 

The  graphs  must  not  be  understood  as  analogous  to  the  filling 
in  of  the  points  of  a  probable  curve  between  known  points,  as  in 
this  case  the  points  represent  discrete  series  and  there  are  no 
possible  points  which  might  be  computed  between  them.  Only 
the  known  points  are  significant  therefore,  the  lines  joining 
them  having  been  added  to  distinguish  the  trend  of  the  series 
and  make  it  more  easily  comprehended  by  the  eye. 

The  ordinates  for  the  series  with  shadows  would  correspond 
pretty  closely  with  the  ordinates  for  the  shadowless  series  with 
which  they  belong  ;  but,  as  previously  noted,  the  two  classes  of 
series  with  shadows  were  not  distributed  regularly  over  the  in- 
terval covered  by  the  shadowless  series.  In  the  case  of  one  of 
the  subjects,  for  example,  the  fall  of  the  lots  was  such  that  most 
of  the  series  with  illusion  '  long  '  occurred  at  the  upper  position 
of  the  graph  for  the  shadowless  series,  and  those  with  illusion 
'  short '  at  the  lower  positions. 

It  would,  therefore,  be  manifestly  incorrect  to  compare  series 
corresponding  to  the  upper  part  of  the  graph  with  series  corre- 
sponding to  both  upper  and  lower  parts,  as  this  would  bring  in 
a   difference   due  merely  to  the   progress   of  the   experiment. 


Table  IV. 

AVERAGE  MEAN  EQUALITY  POINTS. 


Subject. 


S. 
W. 
R. 
A. 


Illusion  Long. 

Diflf. 

Shadowless. 

Shadow. 

— 6.42 

+2-37 
—3-57 
—0.37 

-5-8 

+2.77 

—3-40 
+0.46 

+  .62 
+  •40 

+  ■17 
+  .83 

Illusion  Short. 


Shadowless. 


—5-. 57 
+2.65 
— 2.40 
+1.06 


Shadow. 


—5-75 
+  1-75 
—3-45 
+0.78 


Diflf. 


-  .18 

-  .10 
-1.05 


Hence  in  computing  the  averages,  those  for  the  shadowless 
series  which  were  taken  at  the  same  time  as  the  series  with  the 
illusion  '  long  '  were  kept  separate  from  the  averages  for  the 
shadowless  series  taken  at  the  same  time  as  the  series  in  which 
the  illusion  was  '  short.'  In  other  words,  the  averages  for  the 
two  classes  of  pairs,  as  distinguished  by  the  direction  of  the 


CALIFORNIA    PSYCHOLOGICAL   LABORATORY. 


449 


illusion,  were  taken  independently.     The  results  for  this  opera- 
tion are  given  in  Table  IV. 

The  figures  in  the  first,  second,  fourth  and  fifth  columns  of 
this  table  represent  the  distance  in  millimeters  from  the  actual 


Fig.  7. 


Fig.  8. 


equality  point  to  the  average  mean  equality  point  for  each  group 
of  series  as  indicated  by  the  column  headings.  Negative  dis- 
tances are  measured  from  the  actual  equality  point  towards  the 
center  of  the  line  in  the  illusion-figure,  and  positive  distances  in 


45 o  KNIGHT  DUNLAP. 

the  opposite  direction.  The  figures  in  the  third  and  sixth  col- 
umns give  the  differences  of  the  averages,  and  hence  directly 
the  average  change  in  length  of  the  right  segment  when  the 
imperceptible  shadows  were  present. 

It  will  be  seen  from  Table  IV.  that  in  every  case  the  average 
mean  equality  point  for  the  series  with  shadows  is  farther  out 
than  that  for  the  shadowless  series  when  the  illusion  is  '  long,' 
and  just  the  reverse  when  the  illusion  is  '  short ' ;  which  is  ex- 
actly what  might  be  expected  if  the  illusion  were  really  opera- 
tive. This  unanimity  is  certainly  strongly  in  favor  of  the  theory 
that  the  imperceptible  shadows  actually  affect  the  judgment. 
The  difference  here,  as  in  the  other  comparisons,  is  slight,  but 
we  should  hardly  expect  to  get  more  than  a  slight  effect  from 
the  shadows  under  the  circumstances. 

This  method  of  comparison  by  means  of  equality  points  nec- 
essarily leaves  out  of  account  certain  scattering  judgments  which 
are  bound  to  occur  from  time  to  time,  and  which  are  ignored  by 
the  fixed  rules  under  which  the  mean  equality  point  was  deter- 
mined in  each-  series.  We  must,  therefore,  have  some  other 
method  of  comparison  which  shall  take  these  into  account,  al- 
though their  importance  is  not  so  great  as  is  that  of  the  more 
regularly  occurring  judgments.  The  sporadic  judgment,  contra- 
dicted by  those  which  immediately  precede  and  follow  it,  is  of 
course  largely  due  to  a  sudden  subjective  change  in  the  obser- 
ver, but  its  significance  lies  in  the  fact  that  the  objective  condi- 
tions might  allow  these  subjective  conditions  to  be  more  effec- 
tive in  one  case  than  in  another. 

The  method  adopted  for  doing  justice  to  these  scattering 
judgments  was  the  comparison  of  the  total  number  of  judgments 
of  each  kind  {i.  e.,  '  longer,'  '  shorter,'  and  '  equal '  or  '  doubt- 
ful ')  for  each  value  of  the  variable  lines  on  the  screen,  for  each 
of  the  two  classes  of  series  with  the  illusion  shadows,  with  the 
corresponding  classes  without  the  shadows.  Thus,  for  example, 
the  totals  of  the  different  kinds  of  judgments  when  the  variable 
was  23.5  cm.  (the  standard  being  25  cm.),  when  the  illusion 
was  '  long,'  were  compared  with  the  totals  for  the  same  point 
in  the  corresponding  shadowless  series ;  and  so  for  all  of  the 
other  lengths  of  the  variable  which  were  used  in  the  experiment. 


CALIFORNIA    PSYCHOLOGICAL   LABORATORY. 


451 


Here  as  before,  the  precaution  was  taken  to  compare  each  of 
the  two  classes  of  series  in  which  the  shadows  were  present 
only  with  the  shadowless  series  taken  in  the  same  sets. 

There    being    three    kinds    of    judgments,    viz.,    'longer,' 


Fig.  II. 


Fig.  12. 


'  shorter '  and  '  equal '  or  '  doubtful,'  there  were  then  for  each 
class  three  totals  for  each  point  in  the  scale.  As  each  of  these 
totals  is  significant  only  in  so  far  as  account  is  taken  of  the  dis- 
tribution of  the  remaining  judgments  between  the  two  remain- 


452  KNIGHT  DUN  LAP. 

ing  totals,  no  direct  comparison  of  the  total  judgments  '  longer,' 
e.  g.,  in  the  shadowless  series,  with  similar  judgments  in  the 
opposite  series  could  be  made  with  advantage.  Accordingly 
the  judgments  of  '  short '  were  taken  as  negative,  the  judg- 
ments of  '  long '  as  positive,  and  the  judgments  of  *  equal '  or 
'  doubtful '  as  zero.  The  algebraic  sum  of  these  judgments 
then,  at  a  single  point  on  the  scale  when  the  shadows  were 
present,  or,  on  the  other  hand,  when  they  were  absent,  fairly 
represents  the  character  of  the  total  of  the  judgments  at  that 
point.  As  the  series  were  always  begvm  well  wathin  the  region 
of  apparent  '  shortness '  and  ended  well  outside  of  the  region  of 
equality,  it  was  assumed  that  it  was  possible  to  supply  judg- 
ments at  either  end  of  those  series  that  did  not  reach  the  limits 
of  the  extent  of  the  scale  taken  for  comparison,  thus  keeping 
equal  the  total  number  of  judgments  throughout  the  scale. 

Figs.  5  to  12  give  in  a  graphic  form  the  results  of  this  com- 
parison. The  abscissas  represent  the  different  lengths  of  the 
variable  line  expressed  as  distances  in  millimeters  from  the 
point  where  standard  and  variable  were  equal ;  negative  values, 
of  course,  representing  a  variable  shorter  than  the  standard, 
and  positive  a  longer.  Hence  the  values  here  given,  plus 
twenty-five  centimeters,  show  the  actual  length  of  the  variable. 
The  ordinates  represent  the  algebraic  sum  of  positive,  negative 
and  zero  judgments.  The  continuous  line  gives  the  value  for 
shadowless  series,  the  dotted  line  that  for  series  with  shadows — 
in  Figs.  5  to  8  so  placed  as  to  give  the  illusion  '  short' ;  in  Figs. 
9  to  12  '  long.' 

When  treated  in  this  way  the  results  are  less  striking  than  in 
the  case  of  the  tables  of  general  averages.  If  an  effect  of  im- 
perceptible shadows  were  to  appear  in  the  graphs,  it  would  in 
Figs.  5  to  8  be  evidenced  by  the  fact  that  the  ordinates  of 
points  on  the  dotted  lines  would  incline  more  toward  positive 
values  than  the  corresponding  ordinates  of  the  continuous  lines  ; 
and  more  toward  negative  values  in  Figs.  8  to  12.  This  would 
bring  the  dotted  line  to  the  left  of  the  continuous  line  in  the 
first  group  of  figures,  and  to  the  right  in  the  second  group.  In 
some  of  the  actual  curves,  however,  the  dotted  line  shows  no  de- 
cided tendency  either  way  (Figs.  5,  8  and  9).     In  Figs.  6,  10  and 


CALIFORNIA    PSYCHOLOGICAL   LABORATORY.  453 

II  the  relation  is  faintly  in  accord  with  what  we  should  expect 
if  the  shadows  were  effective  ;  while  in  7  and  12  the  agreement 
is  quite  striking.  If  this  accord  were  a  mere  matter  of  chance, 
several  of  the  curves  ought  to  be  not  simply  neutral,  but  posi- 
tively opposed  to  this  course.  None  of  the  graphs,  however, 
has  this  character.  So  that,  on  the  whole,  this  third  mode  of 
treating  the  results  also  is  favorable  to  the  view  that  the  shadows 
were  operative  in  determining  the  judgment. 

We  may  now  sum  up  the  results  of  our  investigation.  We 
have  found  three  main  points.  First,  when  we  compare  the 
series  set  by  set  as  they  were  taken,  we  find  that  for  each  sub- 
ject the  large  majority  of  the  sets  compare  as  they  should  if 
the  illusion  were  operative.  Second,  we  find  that  the  averages 
of  the  sets  compare  without  exception  as  they  should  under  the 
foregoing  hypothesis,  a  result  which  does  not  necessarily  follow 
from  the  foregoing  result.  Third,  we  find  that  the  totals  of 
the  judgments  at  the  various  points  on  the  scale  are,  to  a  re- 
markable extent,  in  conformity  with  the  same  hypothesis. 
These  three  methods  of  comparison  cover  every  relation  of  the 
series  which  can  fairly  demand  attention,  and  hence  may  be 
taken  as  exhaustive  of  the  results  of  the   present   experiment. 

A  question  of  such  importance  as  that  with  which  the  present 
discussion  deals  requires,  however,  the  maximum  of  careful  in- 
vestigation before  we  dare  call  it  settled.  The  results  detailed 
above  strongly  suggest  that  the  imperceptible  illusion-figure  is  ac- 
tive in  producing  psychical  results,  but  for  the  sake  of  conclusive- 
ness additional  experiments  should  be  carried  out  so  as  to  permit 
the  comparison  of  series  in  which  the  shadows  are  in  one  posi- 
tion directly  with  other  series  in  which  the  shadows  are  in  the 
opposite  position,  using  a  modification  of  the  method  of  right 
and  wrong  cases,  consisting  in  plotting  the  error  curve  for  the 
progressive  intensities  of  the  shadows  by  the  method  of  Least 
Squares,  and  then  comparing  this  with  the  empirical  results 
obtained  by  the  actual  trial  of  the  different  intensities.  This 
method  of  procedure  is  not  absolutely  necessary,  but  is  advis- 
able on  account  of  the  added  satisfaction  derived  from  ap- 
proaching the  same  problem  by  diverse  methods. 


'Hio^ejoqin  |i!3!!o|oi)3^ 

B|Ujoji|ea  JO  \spm 


V 


REPPvINTED  FROM 

VOL  IX.    No.  5.  September,  1902. 

THE 

Psychological  Review 

EDITED  BY 

J.  McKEEN  CATTELL  J.  MARK  BALDWIN 

Columbia  Universitt  Princeton  University 

with  the  co-operation  of 
ALFRED  BINET,  ficoLE  DES  HAOTES-fiTUDES,  Paris;  JOHN  DEWEY,  H.  H.  DONALD- 
SON,  University  of  Chicago;  G.  S.  FULLERTON,  University  of  Pennsylvania; 
G.  H.  HOWISON,  University  of  California;  JOSEPH  JASTROW,  Uni- 
versity OF  Wisconsin;    G.  T.  LADD,  Yale    University;   HUGO 
MONSTERBERG,  Harvard  University;  M.  ALLEN  STARR, 
College  OF  Physicians  AND  Surgeons,  New  York;  CARL 
STUMPF,  University,  Berun;   JAMES  SULLY, 
University  College,  London. 

H.  C.  WARREN,  Princeton  University,  Associate  Editor  and  Business  Manager. 


STUDIES    FROM    THE    PSYCHOLOGICAL    LABORATORY 
OF  THE   UNIVERSITY  OF   CALIFORNIA. 

COMMUNICATED   BY   PROFESSOR   GEORGE   M.    STRATTON. 

III.     Visible  Motion  and  the  Space  Threshold. 
BY   PROFESSOR   GEORGE   M.    STRATTON. 

V.     The   Effect  of  Subdivisions  on  the  Visual  Estimate  of  Time. 
BY   MABEL   LORENA   NELSON. 


PUBHSHRD   BI-MONTHLY    BY 

THE  MACMILLAN  COMPANY, 

41  N.  QUEEN  ST.,  LANCASTER,  PA. 

66    FIFTH    AVENUE,    NEW    YORK. 

Agent:  G.   E.  STECHERT,  London  (2  Star  Yard,  Carey  St.,  W.  C) 

Lbipzic  (Hospital  St.,  10);   Paris  (76  rue  dc  Rennes). 


[Reprinted  from  The  Psychological  Review,  Vol.  IX.,  No.  5,  Sept.,  1902.] 


STUDIES    FROM   THE   PSYCHOLOGICAL   LABORA^ 

TORY   OF   THE   UNIVERSITY   OF 

CALIFORNIA. 

COMMUNICATED  BY  PROFESSOR  GEORGE  M.   STRATTON. 

III.     Visible  Motion  and  the  Space  Threshold. 

BY  PROFESSOR  GEORGE  M.  STRATTON. 

For  some  time  it  has  been  argued  that  the  perception  of 
motion  has  no  immediate  connection  with  the  discrimination  of 
positions  in  space.  It  is  held  that  the  two  processes  are  psy- 
chologically independent,  and  that  we  become  aware  of  motion 
by  a  direct  and  simple  sense  of  the  motion  itself,  and  not  by 
appreciating  that  the  object  occupies  distinct  localities. 

This  paradox  is  supported  in  part  by  the  fact  that  a  move- 
ment in  the  out-lying  portions  of  the  visual  field  can  be  readily 
seen  when  the  movement  has  a  far  less  extent  than  is  required 
to  give  to  two  motionless  objects  a  perceptible  difference  of  posi- 
tion,— a  fact  apparently  first  observed  by  Exner.  To  state  the 
matter  in  the  words  of  Professor  James  :  "  One's  fingers  when 
cast  upon  the  peripheral  portions  of  the  retina  cannot  be 
counted — that  is  to  say,  the  five  retinal  tracts  which  they  occupy 
are  not  distinctly  apprehended  by  the  mind  as  five  separate 
positions  in  space — and  yet  the  slightest  movement  of  the  fingers 
is  most  vividly  perceived  as  movement  and  nothing  else.  It  is 
thus  certain  that  our  sense  of  movement,  being  so  much  more 
delicate  than  our  sense  of  position,  cannot  possibly  be  derived 
from  it.   *  *  *  Movement  is  a  primitive  form  of  sensibility."^ 

1 '  Principles  of  Psychology,'  II.,  172. 

433 


Onhefsit)  of  California 

Psyctiological  Laboratoni. 


434  GEORGE  M.  STRATTON. 

One  may  rightly  have  some  antecedent  hesitancy,  I  believe, 
in  regard  to  James'  interpretation.  Even  admitting  the  facts  he 
offers,  one  need  by  no  means  draw  his  conclusion.  For  the 
alleged  sense  of  motion,  if  it  really  is  a  sense  of  motion^  brings 
in  a  spatial  report.  The  changes  of  which  it  makes  us  aware 
are  preceptibly  different  from  alterations  merely  of  intensity  or 
of  color.  Even  though  we  may  be  unable  to  tell  the  direction 
of  the  motion,  the  motion  itself  is  a  change  of  position,  and  is 
dimly  appreciated  as  such.  Instead  of  saying,  then,  that  the 
experiments  cited  are  evidence  that  the  sense  of  movement  is  so 
much  more  delicate  than  the  sense  of  position,  it  would  be  more 
exact  to  say  that  they  show  that  the  discrimination  of  positions 
during  movement  is  much  finer  than  the  discrimination  of  posi- 
tions at  rest.  It  is  not  really  an  antithesis  between  '  motion ' 
and  '  differences  of  position,'  but  between  differences  of  position 
under  two  contrasting  sets  of  conditions,  motion  being  but  a 
special  mode  of  testing  our  power  of  local  discrimination.  The 
truth  seems  to  be  that  there  are  various  ways  of  measuring  this 
power — among  others,  by  the  simultaneous  presentation  of  two 
lights  in  different  places,  by  their  successive  presentation,  or  by 
a  continuous  movement  of  a  single  light  from  one  position  to 
another.  We  have  no  right  to  assume  (as  Professor  James 
seems  to  do)  that  the  first  of  these  methods  is  the  only  one  that 
gives  the  true  space-threshold,  and  that  the  results  of  the  third, 
if  finer,  are  indications  of  a  process  different  in  kind.  The 
second  method  also  gives  finer  results  than  the  first,  and  yet  no 
one,  so  far  as  I  know,  has  thought  that  the  finer  space  results  ob- 
tained by  successive  stimulation  implied  some  special  and  primi- 
tive form  of  sensibility  different  from  that  which  is  involved  in 
discriminating  simultaneous  impressions.  Why,  then,  should 
we  jump  to  this  conclusion  when  the  conditions  of  space-per- 
ception are  only  slightly  altered  farther,  making  the  successive 
stimulation  spatially  continuous  instead  of  discrete? 

Admitting  the  facts  adduced,  then  it  by  no  means  follows  that 
we  have  a  primitive  sense  of  movement,  independent  of  spatial 
discrimination.  But  at  least  so  far  as  space  is  concerned,  the 
facts  themselves  are    not  unquestionable.     Some  experiments 


VISIBLE  MOTION  AND  SPACE  THRESHOLD.  435 

by  Stern,  reported  in  1894/  already  raised  a  doubt  here.  Stern 
found  that  when  retinal  irradiation  was  decidedly  reduced,  the 
shortest  perceptible  movement  was  not  appreciably  less  than  the 
space-threshold  as  determined  without  movement.  He  conse- 
quently inferred  that  there  was  no  ground  for  assuming  a 
specific  and  unique  sense  of  movement.  But  the  test  of  motion- 
less space-discrimination  used  by  Stern  is  itself  perhaps  not 
fully  convincing.  He  departed  from  the  method  employed  by 
Helmholtz  and  others  —  the  method  by  parallel  lines  brought 
closer  and  closer  together  until  they  almost  fused  —  and, 
instead,  took  as  the  threshold  that  width  of  a  single  dark 
line  that  was  just  doubtfully  perceptible  against  a  light  back- 
ground. The  assumption  here  seems  to  be  that  the  line  is  a  gap 
or  interruption  of  the  white  surface,  and  implies  a  local  dis- 
crimination of  the  two  borders  of  white  against  the  line  which 
divides  them.  But  if  we  regard  black  as  a  positive  impression, 
as  it  would  seem  we  must,  there  would  appear  to  be  no  reason 
why  a  consistent  development  of  this  method  would  not  require 
us  to  accept  the  apparent  diameter  of  a  just  perceptible  fixed 
star  as  a  still  more  accurate  measure  of  local  discrimination. 
The  width  of  the  dark  line  in  Stern's  experiments  is  probably 
of  importance  only  in  a  secondary  way,  by  affecting  the  inten- 
sity of  the  impression  of  black.  This  suspicion  is  strengthened 
by  the  fact  that  with  some  slight  improvements  in  the  conditions 
of  observation  in  our  laboratory,  while  still  remaining  true  to 
the  general  principle  of  Stern's  method,  the  threshold  takes  an 
astonishing  drop.  One  of  my  students,  Mr.  Gilbertson,  finds 
that  the  width  of  the  black  line  visible  against  white,  instead  of 
being  15"  angular  measure,  as  Stern  found  under  his  condi- 
tions, may  be  even  less  than  2.5". 

For  this  reason  it  seemed  well  to  try  some  experiments  in 
which  the  threshold  of  motion  and  that  of  local  discrimination 
might  be  compared  without  so  much  doubt  as  to  the  really 
spatial  character  of  this  local  discrimination.  The  experi- 
ments here  reported  fall  into  two  groups,  the  first  with  indirect, 
the  second  with  foveal  vision. 

^Die  Wahrnehmung  von  Bewegungen  vermittelst  des  Auges,  Zeitsch.  f. 
Psychol,  u.  Physiol,  d.  Sinnesorg.,  VII.,  321. 


43^  GEORGE  M.  STRATTON. 


t  f 

Fig.  I. 

I.  Experiments  with  Indirect  Vision. — The  observer,  in 
Fig.  I,  sat  in  a  half-darkened  room  and  judged  the  character  of 
the  light-stimulus  seen  through  a  narrow  vertical  slit  /  about  ^ 
mm.  wide  in  a  screen  ^S"  before  him.  The  fixation  pointy  was 
5°  to  the  right  of  the  slit  in  one  set  of  experiments  and  30°  to 
the  right  in  the  other,  the  distance  from  the  observer  to  the 
screen  being  in  these  two  cases  2  m.  and  i  m.,  respectively. 
When  the  aim  was  to  determine  the  threshold  of  motion,  a 
bright  point  of  light  moved  from  a  fixed  position  upward  or 
downward  in  the  slit,  while  the  local  discrimination  was  tested 
by  two  separate  motionless  points  of  light  which  appeared  the 
one  above  the  other  and  in  immediate  succession.  The  extent 
of  movement,  in  the  one  case,  and  of  spatial  separation  in  the 
other,  were  of  course  accurately  varied  to  determine  the 
threshold. 

This  variation,  along  with  a  constancy  of  those  conditions 
that  should  remain  constant,  was  brought  about  by  an  arrange- 
ment behind  the  screen,  consistmg  chiefly  of  a  pendulum  Z' carry- 
ing a  smaller  slitted  screen  S' ^  which  in  swinging  past  the  slit 
/  allowed  light  to  pass  to  the  observer  from  a  white  surface  w 
evenly  illuminated  by  an  electric  lamp,  L.  The  pendulum  was 
so  controlled  by  the  electromagnets  e  and  e'  as  to  give  a  single 
swing  from  a  fixed  point  10°  from  the  vertical  and  be  caught  at 
the  end  of  its  course  on  the  other  side.  The  back-swing  in 
preparation  for  the  next  experiment  was  concealed  from  the 
observer.  The  length  of  the  pendulum  was  regulated  to  give 
a  single  oscillation  in  one  second. 

In  Fig.  2  there  is  represented  in  diagram  the  screen  S'  that 
was  carried  by  the  pendulum  when  the  aim  was  to  give  the 
observer   a  moving  point  of  light.     The  main  feature  of  this 


VISIBLE  MOTION  AND  SPACE  THRESHOLD. 


437 


screen  was  a  movable  circular  disc  Z>,  from  whose  center,  c^ 
there  passed  to  the  periphery  a  slit  c^,  ^  mm.  in  width,  forming 
an  arc  of  the  circle  whose  radius  was  the  distance  from  C  to 
the  point  of  suspension  of  the  pendulum  (70  cm.).     When  the 


Fig.  2. 

disc  was  so  set  that  the  center  of  this  arc  coincided  with  the 
point  of  suspension  of  the  pendulum,  the  point  of  light  which 
came  to  the  observer  as  this  arc-slit  swung  past  the  vertical  slit 
/  in  the  stationary  screen  S  in  Fig.  i  had  no  apparent  motion 
whatever.  A  change  of  the  disc's  position,  however,  so  that 
the  slit  took  the  position  r^',  would  cause  an  apparent  upward 
motion  of  the  point  of  light,  the  extent  of  which  in  angular 
measure,  from  the  point  of  view  of  the  observer,  could  readily 
be  calculated.  A  scale  in  terms  of  such  angular  measurement 
was  placed  along  the  circumference  of  the  disc  so  that  this 
could  be  set  for  any  extent  of  motion  desired.  But  since  it 
seemed  best  to  keep  the  duration  of  the  movement  exactly  the 
same  as  the  duration  of  the  stimulus  in  the  corresponding  set  of 
experiments  with  motionless  points,  this  constancy,  in  spite  of 
the  varying  positions  of  the  disc,  was  maintained  by  the  fact 
that  the  screen  S'  was  continuous  behind  the  disc  D  with  the 
exception  of  an  opening  klmn,  whose  boundaries  kl  and  7nn 
were  radii  of  the  circle  mentioned  above,  the  center  of  which 
was  the  point  of  suspension  of  the  pendulum.  It  need  only  be 
added  that, this  screen  was  wide  enough  to  conceal  the  surface 
w  in  Fig.  I,  when  the  pendulum  was  at  either  limit  of  its  ex- 
cursion. 


43S 


GEORGE  M.  STRATTON. 


For  the  experiments  on  the  discrimination  of  position  with- 
out movement,  a  different  screen  was  substituted  upon  the 
pendulum,  yet  with  a  similar  arc-slit  similarly  centered.  But 
in  this  case,  instead  of  revolving  the  slit  about  a  central  point, 
one  half  of  the  slit  could  be  shifted  slightly  up  or  down,  along 
the  radius  of  the  circle  of  which  the  arc  was  a  portion,  as  in 


S' 


Fig.  3. 

Fig.  3.  As  the  pendulum  made  its  single  swing,  there  thus 
appeared  to  the  observer  in  immediate  succession  two  separate 
points  of  light,  the  amount  of  whose  separation  could  be  accu- 
rately varied  by  the  experimenter. 

In  the  preliminary  experiments,  the  well-known  method  of 
*  minimal  changes '  was  employed,  but  the  observers  soon 
showed  themselves  so  much  influenced  by  expectation  that  no 
reliable  determination  of  the  thresholds  seemed  possible  by  this 
means.  The  method  of  '  serial  groups,'  hereinafter  described, 
was  found  more  satisfactory.  The  adoption  of  successive 
stimuli  to  measure  the  local  discrimination  without  movement, 
was  for  the  purpose  of  avoiding  some  of  the  worst  difficulties 
from  irradiation.  Two  points  of  light  when  presented  simul- 
taneously will  often  produce  a  blur  that  is  perceptibly  extended 
(and  consequently  spatial),  and  yet  two  separate  nuclei  of  light 
are  not  distinguished  within  this  vague  extent.  According  to 
the  usual  method  of  interpreting  the  results,  we  should  here  be 
below  the  space-threshold,  although,  of  course,  we  are  not. 
What  Tawney  has  already  justly  insisted   on  with  regard  to 


VISIBLE  MOTION  AND  SPACE  THRESHOLD. 


439 


tactual  impressions/  that  the  perception  of  two  points  is  not  a 
true  measure  of  the  threshold,  might  consequently  be  repeated 
with  respect  to  vision.  The  fusion  of  the  two  points  is  largely 
obviated  by  the  use  of  successive  stimuli  so  that  the  intensity  of 
the  first  impression  is  perceptibly  lessened  by  the  time  the 
second  is  at  its  height. 

But  the  substitution  of  successive  for  simultaneous  impres- 
sions brings  what  some  might  consider  a  vitiation  of  the  results. 
The  two  points  of  light,  even  when  well  separated,  give  the 
psychological  impression  of  continuous  motion ;  the  light  seems 
to  leap  from  the  position  of  the  first  point  to  that  of  the  second. 
At  the  beginning  it  was  thought  possible  to  separate  those 
judgments  in  which  an  apparent  motion  entered,  and  treat  them 
as  a  questionable  group  by  themselves.  But  when  once  the 
suggestion  of  motion  becomes  fairly  lodged  in  the  observer's 
mind,  it  occurs  so  persistently  and  over  such  a  range  that  this 
attempt  was  renounced.  Since  there  is  no  objective  movement 
here,  however,  and  the  whole  thing  is  really  a  matter  of  sug- 
gestion pure  and  simple,  and  seems  to  me  to  imply  an  underly- 
ing space-discrimination  as  the  basis  of  the  suggestion  itself 
(as  I  have  urged  at  the  beginning  of  this  paper),  the  judgments 
with  subjective  motion  have  been  freely  employed  in  computing 
the  thresholds.  Those  to  whom  these  reasons  do  not  seem  suf- 
ficient may  have  no  such  scruples  over  the  second  group  of  ex- 
periments on  foveal  vision  ;  not  even  suggested  movement  there 
enters  into  the  judgment. 

The  results  of  the  experiments  with  indirect  vision  were  as 
follows  : 


observer. 

Angle  of 
Observation. 

Number  of 
Determinations. 

Discrim.  of  Position. 

Perception  of  Motion. 

Threshold. 

M.  v. 

Threshold. 

M.  V. 

A 

Bd 

Bl 
D 

5° 
30° 

5° 

K 

5° 
30° 

6 

5 
6 

3 
3 
4 

9.2'' 
29.O'' 

7.9' 
18.3' 

7-5' 
63.7' 

1.6' 

5.2' 

■r 

2.2' 

3.3' 
8.7' 

10.4'' 
29.O'' 

8.3' 
21.7' 

6.6' 
70.0' 

1.4' 
3.2' 
1.9' 

5-6' 

2.2' 

lo.o' 

I'The   Perception   of  Two  Points  Not  the  Space  Threshold,'   Psychoi,. 
Review,  II.,  585. 


44°  GEORGE  M.  STRATTON. 

The  table  indicates  that  where  the  conditions  are  practically 
equal,  the  perception  of  movement  has  no  advantage  over  the 
discrimination  of  position  without  objective  movement.  So  far 
as  indirect  vision  is  concerned,  the  theory  that  the  two  processes 
are  psychologically  independent  here  finds  no  support. 

II.  Experiments  with  Direct  Vision. — The  second  group 
of  experiments  dealt  with  the  same  problem  as  the  preceding, 
■with  a  change  merely  in  the  method  of  investigation  and  with  a 
different  portion  of  the  retina^the  foveal  instead  of  the  excen- 
tfic  tegion  of  sight.  On  account  of  the  extraordinary  nicety  of 
our  space  discrimination  under  these  conditions,  the  observer 
was  placed  in  a  distant  building  where  there  was  an  unobstructed 
view  of  one  of  the  laboratory  windows,  the  distance  of  his  station 
from  the  object  to  be  observed  amounting  by  accurate  survey  to 
I20  m.  The  observer  faced  the  north,  and  the  portion  of  the 
laboratory  towards  which  he  looked  sent  back  no  direct  glare 
from  the  sun ;  preliminary  experiments  showed  the  need  of 
regarding  these  things.  The  distance  of  the  observer's  station, 
it  is  true,  was  inconvenient  in  many  ways,  but  this  was  more 
than  offset  by  the  greater  ease  of  observation.  The  naked  eye 
could  now  be  employed,  and  all  the  difficulty  was  avoided  that 
comes  from  the  use  of  a  reducing  lens,  such  as  Stern  found 
necessary.  The  fact  that  the  threshold  of  movement  easily  ran 
dowh  to  about  one  half  of  what  he  reports  shows  the  advantage 
of  these  conditions.  For  the  perception  of  motion  a  strip  of 
white  bristol-board,  8  mm.  wide  by  50  cm.  long,  was  mounted 
vertically  on  a  dead-black  frame  which  could  be  moved  hori- 
zontally before  a  larger  dead-black  background.  From  the 
observer's  station  the  frame  itself  was  invisible,  aud  all  that  one 
saw  was  the  white  line  on  the  large  black  field.  The  move- 
ment of  the  line  was  controlled  by  runners  and  guides  and 
adjustable  stops  on  the  frame,  so  that  the  motion  was  kept  hori- 
zontal and  its  excursion  varied  by  steps  of  i  mm.  The  experi- 
menter moved  the  frame  by  hand,  and  during  any  single  obser- 
vation kept  the  extent  of  the  movement  constant,  and  continued 
the  oscillations  from  the  moment  just  before  the  exposure  of  the  line 
until  the  observer  had  signalled  his  judgment.  In  order  to  insure 
full  justice  to  this  side  of  the  investigation,  the  rate  of  movement 


VISIBLE  MOTION  AND  SPACE  THRESHOLD. 


441 


had,  also,  of  course,  to  be  taken  into  account;  otherwise  some 
velocity  might  be  selected  that  would  not  be  the  most  favorable 
to  perception.  For  this  reason  the  experiments  on  motion  were 
subdivided  into  five  groups,  with  a  rhythm,  respectively,  of  60, 
100,  180,  300,  and  450  single  swings  to  the  minute.  The  rates 
were  maintained  with  reasonable  accuracy  by  the  aid  of  an 
adjustable  pendulum  invisible  to  the  subject  of  the  experiment. 

For  the  corresponding  set  of  experiments  on  the  discrimi- 
nation of  position  without  movement  the  conditions  were  in  all 
respects  the  same,  except  that  for  the  moving  frame  with  its 
single  vertical  line  two  vertical  lines  end-to-end  against  the 
dark  background  were  substituted.  Of  these  two  lines  the  lower 
was  fixed,  while  the  upper  was  capable  of  being  shifted  from 
continuity  with  the  lower  line  to  any  position  to  the  right  or  left, 
remaining  throughout  parallel,  however,  to  its  original  position. 
The  actual  settings  varied  by  steps  of  i  mm.,  and  the  observer 
had  simply  to  judge  whether  the  two  lines  at  any  given  setting 
Were  continuous,  or  in  what  respect  they  spatially  differed.^ 

The  results  of  the  two  sets  of  experiments  under  these  con- 
ditions were  as  follows ; 

Discrimination  of  Position  Without  Movement. 
Thresholds  in  mm. 


Observer  S.                                1 

Obierrer  Y. 

Left. 

Right. 

Left. 

Right. 

4 

7 
3 
7 
3 
4 

4 

5 

5 

5 

3                  : 

6 

6 

4 
5 
6 

7 

3 
6 
6 
6 

4 

AV.       4-3 

4-3 

5.6 

5-0 

The  thresholds  for  the  discrimination  of  position   without 

movement    are    slightly    higher   than    those    obtained    in    my 

previous  study  already  referred  to,  but  the  difference  is  not 

such  as  to  call  for  any  special  comment.     The  thresholds  for 

the  perception  of  movement,  as  affected  by  the  rate  of  move- 

1  For  a  more  detailed  account  of  this  method,  see  my  '  New  Determination 
of  the  Minimum  Visibile  and  its  Bearing  on  Localization  and  Binocular  Depth,' 
Psychol.  Review,  VII.,  429. 


442 


GEORGE  M.  STRATTON. 


Perception  of  Movement. 
Thresholds  in  mm. 


single  Oscillations  per  Minute. 


Observer  S. 


Av. 


II 

i6 

14 

8 


5-5 


450 


4-75 


25 

14 

7 

4 

7 

Observer  Y. 

15 

14 

5 

6 

7 

18 

8 

6 

6 

6 

16 

12 

6 

5 

6 

Av. 

18.5 

12 

6 

5-2 

6.5 

ment,  take  a  somewhat  different  course  from  those  reported  by 
Stern. ^  This  investigator  worked  with  rhythms  of  144,  84  and 
72  vibrations  to  the  second,  and  found  merkTuilrdigerweise  (as  he 
says)  that  the  slowest  movement  was  the  one  most  distinctly  per- 
ceived. In  my  own  results,  it  will  be  seen  that  the  lower  rates, 
those  of  60  and  100,  are  markedly  unfavorable  to  perception, 
with  a  decided  improvement  as  we  pass  to  180  and  300,  the 
threshold  again  rising  slightly  as  the  rate  is  still  farther  in- 
creased. Virtue  here  seems  again  to  lie  in  the  mean.  The 
lower  rates  require  a  considerable  excursion  before  they  can  be 
distinguished  from  rest,  while  the  most  rapid  oscillations  tend  to 
produce  a  mere  indistinctness  rather  than  a  perceptible  swaying 
of  the  object.  I  am  quite  at  a  loss  to  account  for  our  divergent 
results  here,  unless  it  be  that  by  the  word  ^  Schjvingtmgen,'' 
which  Professor  Stern  uses  without  modification,  he  means 
^double  vibrations.'  In  this  event  his  lowest  rate  would  be 
about  midway  between  my  100  and  180,  and  he  would  have 
caught  only  the  dip  of  the  threshold  as  it  comes  out  of  the  region 
where  the  rapidity  of  the  impressions  produces  blur,  without  his 
rates  becoming  slow  enough  to  show  the  upward  trend  of  the 
threshold  again  farther  on.  My  own  subjects,  like  his,  never 
knew  beforehand  the  rate  that  was  being  used,  so  the  dis- 
crepancy cannot  be  explained  in  this  way.  Possibly  the  differ- 
ence is  in  some  way  connected  with  the  fact  that  his  observers 
had  to  look  through  the  lens  of  a  microscope. 

^  Zeitschrift  fur  Psychologic  u.  Physiol,  d.  Sinnesorg .,  VII.,  347. 


VISIBLE  MOTION  AND  SPACE  THRESHOLD.  443 

For  observer  6*,  the  most  favorable  rates  of  motion  give  a 
threshold  of  4  mm.  (about  6.8"  angular  measure)  as  against 
4.3  mm.  (about  7.3")  for  the  discrimination  of  place  —  a  net 
advantage,  for  motion,  of  .3  mm.  or  .5"  of  arc,  on  the  average. 
If,  however,  we  were  to  disregard  averages  and  look  at  the  in- 
dividual determinations,  it  would  appear  that  the  space  dis- 
crimination occurred  as  low  as  3  mm.  (5.1"  of  arc)  ;  while  in 
no  case  does  motion  become  perceptible  below  4  mm.  For  ob- 
server T^  the  mean  threshold  for  position  without  movement  is 
5.3  mm.  (9")  ;  while  the  most  favorable  rate  of  motion  gives 
5.2  mm.  (8.8")  on  the  average.  Here  again  the  minimum 
thresholds  for  position  are  below  the  smallest  for  movement. 
Thus,  from  one  point  of  view,  motion  has  a  slight  advantage 
over  discrimination  without  movement,  which  advantage,  how- 
ever, is  reversed  when  the  numbers  are  differently  regarded. 
But  in  either  case  the  difference  is  too  slight  to  serve  as  a  suf- 
ficient basis  for  entirely  differentiating  the  psychological  pro- 
cesses involved. 

The  results  here,  then,  are  in  substantial  agreement  with 
those  obtained  in  indirect  vision  by  an  independent  method. 
The  doctrine  that  visual  motion  is  a  primitive  form  of  sensibility 
independent  of  local  discrimination  finds  no  experimental  war- 
rant. The  perception  of  motion  seems  to  be  nothing  more  nor 
less  than  the  perception  that  a  sensation  is  changing  its  space 
relations,  the  motion  itself  furnishing  a  decidedly  favorable, 
but  by  no  means  unique,  set  of  conditions  for  appreciating  such 
differences  of  space  relationship.  This  does  not  imply  that  the 
detection  of  movement  always  involves  a  deliberate  comparison 
of  positions  ;  for  the  discrimination  often  undoubtedly  occurs 
at  a  single  psychic  stroke.  But  even  this  apparently  simple 
stroke  is  really  a  complex  act.  It  implies  a  relational  activity 
of  the  mind  which  interprets  and  gives  character  (crude  and 
confused  though  it  be)  to  the  incoming  sensations,  so  that  they 
are  no  longer  blank  impressions,  but  are  impressions  which 
mean  for  us  movement.  The  experiments  thus  go  to  support 
the  view  that  a  fact  of  space  can  never  be  conveyed  to  the  mind 
in  the  form  of  a  pure  sensation  divested  of  all  relationship. 


444  GEORGE  M.   STRATTON. 

IV.     The  Method  of  Serial  Groups. 

BY  PROFESSOR  GEORGE  M.  STRATTON. 

In  the  practical  conduct  of  the  laboratory  one  frequently 
feels  the  shortcomings  of  the  method  of  '  minimal  changes.' 
It  is  undoubtedly  the  best  all-around  mode  of  procedure  yet  de- 
vised, but  in  certain  cases  where  the  conditions  are  exceptional 
it  may  leave  one  quite  itn  Stick.  This  is  especially  true  when 
one  is  dealing  with  minimal  impressions,  where  suggestion  is 
apt  to  find  such  free  play ;  the  observer  may  continue  to  notice 
a  sensation  when  the  stimulus  has  become  suspiciously  weak — 
in  fact  when  no  stimulus  at  all  is  applied.  Thus,  with  certain 
excellent  though  suggestible  subjects,  I  have  found  it  impos- 
sible to  determine  by  the  method  of  minimal  changes,  pure  and 
simple,  the  least  extent  of  visible  motion  that  could  be  per- 
ceived as  motion.  The  subjects  persisted  in  seeing  the  light 
move  on  every  occasion,  whether  there  was  any  actual 
movement  or  not.  The  control  of  the  answers,  by  requiring 
that  the  observer  shall  tell  correctly  some  additional  feature  of 
the  impression — tell,  say,  the  direction  of  the  movement,  or,  if 
the  experiments  be  on  the  least  perceptible  change  of  pressure, 
tell  whether  the  pressure  becomes  heavier  or  lighter  —  may  in 
some  instances  be  helpful.  But  often  this  check  will  hide  the 
very  facts  that  one  wishes  to  ascertain  — the  point  at  which  the 
subject  perceives  motion  and  yet  is  uncertain  of  the  direction, 
or  notice  change  of  pressure  without  being  able  to  say  whether 
the  weight  has  grown  greater  or  less. 

The  usual  resort  in  this  event  is  either  to  a  so-called  '  catch 
experiment '  the  Vextrversuch,  where  no  stimulus  at  all  is  given, 
or  to  the  method  of  right  and  wrong  cases.  The  latter, 
making  use  as  it  does  of  the  law  of  probability,  not  only  re- 
quires an  extremely  large  number  of  observations,  but  there  is 
usually  needed  considerable  preliminary  and  irregular  experi- 
mentation in  order  to  discover  the  conditions  that  will  give  a 
suitable  proportion  of  right  and  wrong  answers.  The  Vexir- 
versuch^  on  the  other  hand,  has  never  been  systematized,  and 
as  it  is   usually  introduced   in    an  irregular  fashion  within  the 


METHOD  OF  SERIAL  GROUPS. 


445 


method  of  minimal  changes,  it  is  apt  to  disturb  the  even  tenor 
of  the  research,  and  disconcert  the  observer  whenever  he  gets 
a  hint  of  what  is  being  done. 

In  the  method  of  serial  groups  here  proposed,  the  attempt  is 
made  to  legitimate  the  '  catch '  experiment,  to  introduce  it  as  a 
continuous  and  regular  element  of  the  procedure,  while  secur- 
ing certain  advantages  both  of  the  method  of  minimal  changes 
and  of  the  method  of  right  and  wrong  cases.  To  give  a  con- 
crete illustration,  suppose  the  following  groups  of  experiments 
be  carried  out  to  determine  the  just  perceptible  extent  of  move- 
ment by  sight,  under  the  conditions  described  in  the  second 
part  of  the  preceding  paper  : 


Group  I. 

Group  Ji. 

Exp.  No. 

Amount  of 
Motion. 

Judgment. 

Exp.  No. 

Amount  of 
Motion. 

Judgment. 

I 
2 

3 
4 
5 
6 

7 
8 

9 

ID 

O 

7  mm. 

7  mm. 

7  mm. 

o 

o 

7  mm. 

o 

o 

7  mm. 

no  motion, 
motion. 

no  motion  X. 

<(         (< 

(i         (( 

motion, 
no  motion. 

motion. 

II 
12 

13 
14 
15 
i6 

17 

i8 

19 
20 

0 

0 

6  mm. 

6  mm. 

0 

6  mm. 

0 

6  mm. 

0 

6  mm. 

no  motion, 
motion. 

no  motion. 

motion, 
no  motion. 

motion, 
slight  motion  X. 

motion. 

Group  III. 

Group  IV. 

Exp.  No. 

Amount  of 
Motion. 

Judgment. 

Exp.  No. 

Amount  of 
Motion. 

Judgment. 

21 

5  mm. 

no  motion  X. 

31 

4  mm. 

very  slight  motion. 

22 

0 

"         " 

32 

0 

no  motion. 

23 

5  mm. 

motion. 

33 

0 

"         «' 

24 

0 

no  motion. 

34 

0 

very  slight  motion  X. 

25 

5  mm. 

"      X. 

35 

4  mm. 

no  motion  X. 

26 

0 

IC                  <( 

36 

0 

(1        i( 

27 

5  mm. 

motion. 

I       37 

4  mm. 

motion. 

28 

0 

no  motion. 

38 

4  mm. 

'< 

29 

0 

(<        (< 

39 

0 

no  motion. 

30 

5  mm. 

motion. 

40 

4  mm. 

X. 

THe  X  shows  the  errors  in  an)'-  group,  and  from  these  the 
threshold  may  be  determined  according  to  any  proportion  of 
correct  and  incorrect  answers  that  may  be  chosen.  In  my  own 
computations  that  group  has  been  taken  as  giving  the  threshold 
beyond  which  less  than  eight  out  of  the  ten  judgments  are 
right.     But  a  detail  like  this,  as  well  as  the  exact  number  of 


446  GEORGE  M.   STRATTON. 

experiments  that  may  best  form  a  '  group,'  might  well  be  con- 
sidered as  subject  to  revision  in  the  light  of  farther  experience, 
and  not  as  an  essential  part  of  the  method.  The  essence  of  the 
matter  is  simply  that  there  should  be  groups  of  experiments  ar- 
ranged in  a  regular  series,  the  amount  of  positive  stimulus,  as 
one  passes  from  group  to  group,  being  graduated  according  to 
the  principle  of  the  method  of  minimal  changes  ;  while  within 
the  limits  of  any  one  group  a  constant  stimulus  is  irregularly 
alternated  with  cases  where  the  stimulus  is  zero,  thus  uniting  in 
the  single  group  the  basal  principle  of  the  method  of  right  and 
wrong  cases  and  that  of  the  Vcxirversuch.  This  may  seem 
provokingly  eclectic,  but  it  is  not  exactly  that ;  the  different 
elements  make  an  organic  union,  and  not  a  mere  patchwork. 
There  is  simply  an  attempt  to  make  systematic  what  experi- 
menters have  frequently  found  themselves  compelled  to  do  in  a 
casual  and  uncritical  way. 

One  may  perhaps  repeat  that  this  method  is  not  proposed  as 
a  general  substitute  for  the  classic  ones  in  use.  It  is  well,  how- 
ever, to  multiply  our  tools  so  that  the  best  may  be  selected  for 
the  special  work  in  hand.  And  this  one  has  been  found  good 
for  certain  purposes,  especially  where  suggestion  plays  a  prom- 
inent role.  The  observer  may  here  know  from  the  very  begin- 
ning the  general  method  of  procedure  ;  he  may  know  that  zero- 
cases  are  to  be  irregularly  alternated  with  those  of  positive 
stimulation,  and  his  expectation  is  therefore  less  *  set '  and  influ- 
ential. The  zero-cases  no  longer  come  in  as  a  kind  of  indig- 
nity upon  the  observer,  as  if  his  word  were  being  questioned. 
The  check  here,  because  of  its  constancy,  ceases  to  excite  any 
feeling.  The  procedure,  moreover,  has  the  virtue  of  the  method 
of  minimal  changes,  in  that  the  threshold  is  ascertained  empir- 
ically, by  actually  crossing  it.  And  while  the  principle  of  right 
and  wrong  cases  is  employed,  with  the  powerful  control  which 
that  always  brings,  yet  there  is  no  introduction  of  the  intricate 
calculus  of  probability  and  a  certain  darkness  that  always  shad- 
ows its  results.  It  is  true  that  the  application  of  the  method  of 
serial  groups  is  in  a  certain  sense  cumbersome,  as  compared 
with  the  method  of  minimal  changes,  since  in  a  given  time 
fewer   determinations  of  the  threshold  can  be  obtained.     But 


VISUAL  ESTIMATE  OF  TIME.  447 

with  suitable  rests  between  the  '  groups,'  there  is  no  need  of 
there  being  greater  fatigue  to  the  observer  in  the  one  case  than 
in  the  other ;  and  while  the  determinations  ma}^  be  fewer  for  the 
time  expended,  yet  in  most  cases  I  have  found  that  they  more 
than  make  up  in  weight  what  they  lack  in  number. 

V.  The    Effect    of    Subdivisions    on    the    Visual    Esti- 
mate OF  Time. 

BY  MABEIv  LORENA  NELSON. 

It  has  been  found  by  Dr.  Ernst  Meumann  and  others  that  the 
estimate  of  small  time-intervals  is  influenced  by  the  number  of 
stimuli  that  fall  within  the  interval.  In  the  space  illusion 
of  sight,  a  single  division  of  the  standard  will  cause  it  to  be 
underestimated,  while  more  divisions  will  cause  an  overestima- 
tion ;  in  touch,  the  effect  of  subdivisions  depends  on  the  abso- 
lute length  of  the  standard.^ 

My  object,  in  the  following  experiments,  was  to  determine 
the  effect  of  single  and  multiple  divisions  of  the  standard  on 
times  of  longer  duration  than  those  investigated  by  Dr.  Meu- 
mann, and  to  discover  if  there  existed  a  temporal  illusion  com- 
parable to  the  space  illusions  of  sight  and  touch. 

In  Dr.  Meumann's  investigation  of  time  intervals,  he  com- 
pares an  '  empty  '  time  —  one  bounded  by  two  impressions  — 
with  times  '  filled  '  with  either  three,  five,  six,  nine  or  twelve 
impressions,  inclusive  of  the  terminal  stimuli.  His  results  ^  are, 
that  for  times  from  one  tenth  of  a  second  to  about  four  seconds, 
when  the  filled  time  comes  first,  the  error  in  estimating  is  con- 
stantly positive  —  while  for  longer  times  the  error  is  negative. 

This  seems  to  indicate  that  the  effect  of  the  filling  is  posi- 
tive for  the  short  times,  and  negative  for  the  longer.  The  error 
found  by  Dr.  Meumann  is,  however,  not  due  to  the  filling 
alone,  but  is  the  result  of  two  factors.  It  is  generally  conceded 
that  even  when  two  empty  times  are  compared,  there  is  a  simi- 
lar constant  error,  positive  for  short  times,  negative  for  longer. 

'See  the  paper  by  Miss  Alice  Robertson,  on  '"  Geometric- Optical '  Illu- 
sions in  Touch '  "  to  be  published  subsequently. 

2  '  Beitrage  zur  Psychologie  des  Zeitbewusstseins,'  Phil.  Studien,  XII. ,  p.  1 27. 


448  MABEL  LORENA  NELSON. 

That  there  is  a  difference  other  than  this  constant  error  which 
must  be  attributed  to  the  filling,  Dr.  Meumann  shows — for,  in 
those  cases  where  the  order  is  reversed,  the  empty  time  coming 
first,  the  sign  of  the  error  is  also  reversed  —  but  the  quantity  of 
the  error  due  to  the  filling  alone  he  does  not  show,  as  these 
two  factors  are  not  quantitatively  separated. 

The  longest  period  chosen  by  Dr.  Meumann  was  nine 
seconds.  The  following  experiments  were  taken  to  determine 
what  effect  the  filling  would  have  on  longer  periods,  durations 
of  several  minutes. 

The  intervals  chosen  were  one  half,  one,  two,  four,  six  and 
ten  minutes ;  the  filling,  sensations  of  light. 

Under  each  interval  two  sets  of  estimates  were  taken.  The 
first,  where  the  standard  and  compared  times  were  both  empty 
(marked  E-E  in  the  tables)  was  taken  to  determine  the  constant 
error  due  to  the  mere  sequence  of  the  two  intervals.  In  the 
second  set  one  of  the  times  was  always  empty  and  the  other 
filled  {E-F-AXidi  F-E  in  the  tables).  Any  difference  found  be- 
tween the  estimates  of  the  two  sets,  for  a  given  interval,  must 
be  due  to  the  filling. 

The  results  as  given  in  the  tables  are  computed  from  five 
estimates  under  each  interval  for  the  empty  time,  and  five  for 
the  filled.  The  average  of  the  estimates  is  given ;  the  differ- 
ence between  this  and  the  standard  interval,  expressed  as  a  per 
cent,  of  the  standard  ;  and  the  mean  variation  from  the  average 
estimate,  expressed  as  a  per  cent,  of  the  average.  A  second  basis 
of  comparison  is  the  median  of  the  five  estimates  and  its  differ- 
ence, as  a  percentage,  from  the  standard  interval. 

The  effect  due  to  the  filling  for  each  interval  is  found  by 
subtracting  the  constant  error,  when  both  standard  and  compared 
times  are  empty,  from  the  error  in  estimating  when  one  of  the 
times  is  filled.  When  the  difference  due  to  the  filling  in  Tables 
I.  and  II.  has  a  positive  sign,  it  must  be  taken  to  mean  that  the 
filled  time  seemed  shorter  than  an  empty  one  of  the  same  length. 
In  Tables  III.,  IV.  and  V.,  however,  the  order  is  reversed,  the 
filled  time  being  taken  as  the  standard  —  a  positive  error  here 
would  indicate  that  the  filled  time  seemed  longer  than  the 
empty. 


VISUAL  ESTIMATE  OF  TIME. 


449 


The  method  of  taking  the  experiments  was  as  follows  :  The 
subject  sat  in  a  darkened  room  before  a  screen  and  saw  through 
an  aperture  in  the  screen,  5  mm.  wide  by  10  mm.  in  height, 
flashes  of  light  through  a  noiseless  pendulum  behind.  A  flash 
of  light  marked  the  beginning  of  an  empty  time,  a  second  flash 
its  end.  During  the  filled  time  the  subject  saw  a  flash  of  light 
every  half  second.  There  was  in  every  experiment  a  pause  of 
two  seconds  between  the  closing  flash  of  the  standard  and  the 
first  flash  of  the  compared  time.  The  end  of  the  compared  time 
was  marked  off  by  a  word  from  the  subject  when  a  time  had 
elapsed  which  seemed  to  him  equal  to  the  standard. 

In  the  first  group  of  experiments  the  standard  time  was  al- 
ways empty.  Two  subjects  were  taken,  D  and  7?;  the  results 
are  found  in  Tables  I.  and  II.  The  great  difficulty  my  subjects 
found,  in  the  long  intervals,  in  keeping  their  attention  on  the 
length  of  the  standard,  made  it  necessary  to  give  them  some  idea 
of  the  interval  to  be  used.  Accordingly  they  were  told  whether 
the  interval  would  be  short  (one  half  and  one  minute  were  called 
short),  moderate  (two  and  four  minutes),  or  long  (six  and  ten 
minutes),  and  whether  the  compared  time  would  be  filled  or 
empty.  This  was,  of  course,  in  some  respects  a  disadvantage, 
as  it  perhaps  affected  the  lengths  of  the  estimates,  but  as  my  ob- 
ject was  to  compare  the  estimates  of  a  filled  and  an  empty  in- 
terval of  time,  the  results  are  not  invalidated  by  this  guidance, 
as  it  was  given  alike  in  both  sets. 

In  order  that  there  might  be  no  constant  effect  due  to  con- 
trast, the  order  of  using  the  different  lengths  as  standards  was 
not  fixed,  but  was  determined  by  chance.  The  time  occupied 
by  my  work  was  never  more  than  one  hour  at  a  time. 


Table  I. 
Subject  D.    E-E. 


Interval. 

Av.  Estimate. 

D  i, 

M.V.ff 

Median. 

D5« 

M.V.St 

Yz  min. 

1  " 

2  " 

4    " 

6     " 

10     " 

28.2  sees. 

45.4    " 

1  min.   40.6    " 

2  "      58.2     " 
4     "      56.8    " 
7    "      21.4    " 

—  6 

—  24-3 

—  16 

—  25.7 

—  17 

—  26.4 

27.5 
10.7 
12.6 

30.2 
14.7 
31 

34  sees. 

44    " 

1  min.     40     " 

2  "        26     " 

4     "        43     " 
7     "        22     " 

+  13 

—  26.6 

—  16.6 

—  39-1 

—  26.9 

—  26.6 

19.4 
10.4 
12.6 

33.7 
14.4 

34-2 

450 


MABEL  LORENA  NELSON. 


E-F. 


Yz  min. 

53.4  sees. 

+  78 

40.1 

43  sees. 

+  43-3 

35-3 

I     " 

I  min. 

18.6     " 

+  31 

15-4 

I  mm. 

17     " 

+  28.3 

23-4 

2      " 

2     " 

6.6     " 

+    5-5 

30-4 

I     " 

55     " 

—   4.1 

35-1 

4     " 

4     " 

6.8     " 

+     2.8 

27.1 

4     " 

20     " 

+    8.3 

27.7 

6     " 

6     " 

7-4     " 

+    2 

33-5 

6     " 

53     " 

+  14-7 

27-5 

IO      " 

7     " 

1.8     " 

—  29.7 

18.4 

7     " 

26     " 

-25.6 

16.3 

Difference  due  to  Filling. 


%  min. 

1  " 

2  " 

4    " 

6    " 

10    " 


Average. 


+  84     per  cent. 

+  55-3 

+  21.5 

+  28.5        " 

+  19 

-   3-3        " 


Median. 


+  30     per  cent. 
+  54-9       " 
+  12.5        " 

+  47-4 

+  41.6        " 

+    I 


The  results  as  given  in  Table  I.  show  that  when  the  average 
is  taken  as  the  basis  of  comparison,  the  effect  of  the  filling  on 
the  estimates  in  the  case  of  D  is  very  constant.  In  the  interval 
•of  a  half  minute,  a  filled  time  84  per  cent,  greater  than  the  empty 
is  taken  to  be  its  equal.  The  effect  of  the  filling  seems  to  de- 
crease as  the  length  of  the  interval  increases,  until  at  ten  minutes 
it  is  but  little  or  nothing. 

Table  II. 
Subject  R.    E-E. 


Interval. 

Av.  Estimate. 

D?J 

M.V.  5« 

Median. 

D?f 

M.V.  5« 

Yi  min. 

34.4  sees. 

+  14.6 

26.2 

34  sees. 

+  13 

259 

I     " 

I  min.   12.2     " 

+  20.6 

23.1 

I  min.     13     " 

+  21.6 

23-5 

2     " 

I     "      37-8     " 

-18.5 

12.8 

I     '«        39     " 

—  17.5 

17.4 

4     " 

3     "       12.8     " 

—  19.6 

16.3 

3     "         17     " 

—  17.9 

14-5 

6     " 

3     "      50.2     " 

-36 

18.3 

3     "         II     " 

—  46.9 

29.1 

10     " 

5     "       35-1     " 

—  44 

18 

4     "        55     " 

—  50.8 

I5-I 

E-F. 


Y2  min. 

36.2  sees. 

+  20.6 

33-5 

40  sees. 

+  33-3 

28.5 

I     " 

57.4    " 

—   4-5 

27-3 

54     " 

—  10 

27.4 

2     " 

I  mm. 

47-4     " 

—  10.5 

29.8 

I  min. 

39     " 

—  17-5 

30-7 

4    " 

2     " 

56.2     " 

-26.5 

36.4 

3     " 

7     " 

—  22 

33-1 

6     " 

3     " 

45 

—  37-5 

15-4 

3     " 

33     " 

—  40.8 

17-3 

10     " 

5     " 

33 

—  44-5 

8.4 

5     " 

48     " 

—  42 

7-5 

Difference  due  to  Filling. 


Average. 

Median. 

Yz  min. 

1  " 

2  " 

4     " 

6     " 

10     " 

+  6     per  cent. 
—25.1 

+  8.5        " 

—  6.9        " 

—  1-5 

—  -5 

+20.3  per  cent. 
-31.6 

0            " 

—  4-1 
+  6.1 
+  8.8 

VISUAL  ESTIMATE  OF  TIME. 


451 


With  jR,  Table  II.,  the  filled  time  seems  shorter  than  the 
empty  in  the  intervals  of  one  half  and  two  minutes,  but  for  all 
the  other  times  it  seems  longer,  taking  the  average  as  the  basis 
of  comparison.  The  error  in  the  longest  intervals  is  very  small 
and  its  sign  is  changed  when  the  median  is  taken  instead  of  the 
average. 

In  continuing  the  experiments  I  introduced  the  filling  into 
the  first  or  standard  time,  the  compared  time  being  always 
empty.  We  should,  therefore,  expect  a  reversal  of  sign  in  the 
effect  due  to  the  filling.  I  found  that  after  the  former  practice 
the  subjects  were  able  to  hold  their  attention  to  the  standard 
time  without  any  foreknowledge  as  to  its  length.  In  this  second 
group  of  experiments  they  were  consequently  ignorant  of  the 
character  of  the  interval  to  be  used.  In  all  other  respects  the 
work  was  conducted  exactly  as  before. 

Table  III. 
Subject  D.    E-E. 


Interval. 

Av.  Estimate. 

D?^ 

M.V.  5^ 

Median. 

m 

M  .v.  i 

Yz  min. 

30.8  sees. 

+     2.6 

21.3 

28  sees. 

—   6.6 

21.4 

I     " 

I  min.    10.2    " 

+  17 

29.6 

53     " 

-11.6 

33-3 

2      " 

2     "      25       " 

+  20.8 

16.6 

2  mins.     10     " 

+   8.3 

10 

4    •• 

3     "      31.6    " 

—  II.4 

21.2 

2       "         47     " 

—  34.1 

18.9 

6     " 

4     "      58.9    " 

— 16.9 

17.6 

4      "        50     " 

—  19.4 

13-4 

10     " 

9     "      31.4    " 

—  4.7 

23.8 

10      "        40     " 

+   6.6 

22.2 

F-E. 


Yz  min. 

35.1  sees. 

+  17 

15.8 

33  sees. 

+  10 

13.6 

I     " 

55.4     " 

-    7-6 

29 

46     " 

—  26.6 

26.5 

2     " 

I  min.    26.6     " 

-27.8 

26.7 

I  mm. 

14     " 

-38.3 

22.1 

4     " 

3     "      53 

—   2.9 

18.9 

4     " 

19     " 

+   7.9 

15.9 

6     " 

4     "      43.6     " 

—  18.4 

20.1 

4     " 

22     " 

—  27.2 

18.2 

10     " 

9     "      28.2     " 

—   5-3 

21.7 

10     " 

I     " 

0 

19-5 

Difference  due  to  Filling. 


Average. 

Median. 

Yz  tnin. 

1  " 

2  " 

4     " 

6     " 

10     " 

+  14.4  per  cent. 

—  24.6          " 

—  48.6 
+    8.5 

—  1-5 

—  .6 

+  16.6  per  cent. 

-15 

—  46.6 

+  42 

—  7.8         " 

—  6.6 

The  results  for  Z>,  Table  III.,  show  that  with  two  exceptions 
(one  half  and  four  minutes)  the  difference  due  to  the  filling  has 


45» 


MABEL  LORBNA  NELSON. 


a  negative  sign,  where  in  Table  I.  it  was  positive,  indicating 
that  in  general  the  filled  time  seemed  shorter  than  the  empty. 

Table  IV. 
Subject  R.    E-E. 


Interval. 

Av.  Estimate. 

•ai 

M.V.95 

Median. 

Tif 

VL.V.i 

yi  min. 

28.2  sees. 

—   6 

27.7 

23.5  sees. 

—  21.6 

29-3 

I     " 

I  min.   10.8     " 

+  18 

23-4 

I  min.              " 

0 

24.1 

2       " 

I     "       33-2     " 

—  25-5 

243 

I     "      28 

—  26.6 

245 

4     " 

2     "       20.5     " 

-41.5 

25 

2     "       14        " 

—  44-1 

ib.5 

6     " 

3     "       41-4     " 

-38.5 

19.2 

3     "      56        " 

—  34-4 

I6.7 

lO      " 

6     "       32.9     " 

—  34-5 

25-7 

5     "      54-5     " 

—  40.9 

23.1 

F-E. 


Yz  min. 

31.4  sees. 

+   4.6 

30.3 

37  sees. 

+  23.3 

22.7 

I     " 

I  mm. 

4-7     " 

+   7.8 

7.4 

I  mm. 

2     •' 

+    1.6 

6.9 

2     " 

2     " 

19.4     " 

+  16. 1 

29.2 

2     " 

20    " 

+    1.6 

21.8 

4    " 

2     " 

57.6     ". 

—  26 

28.2 

2     " 

34     " 

-30.5 

29-3 

6     " 

5     " 

52 

—   3-3 

11.6 

6     " 

I     " 

+   0 

10.7 

10     " 

6     " 

15-4     " 

—  34-1 

19.4 

5     " 

49     " 

—  41.8 

19-3 

Difference  due  to  Filling. 


Median. 


+  44.9  per  cent. 

+  1.6 
+  28.2 
+  13-5 
4-34-4 
-      -9 


Subject  R,  in  Table  IV.,  shows  a  positive  difference,  with 
the  exception  of  the  interval  of  one  minute,  where  the  median 
and  average  give  conflicting  results,  and  of  the  interval  of  ten 
minutes,  where  there  is  practically  no  effect. 

We  have  in  the  tables  four  sets  of  figures  that  represent  the 
effect  of  the  filling  on  the  estimates  of  D  and  of  R.  These 
figures  are  based  on  the  average  and  the  median  of  each  of  the 
two  groups  of  experiments.  I  think  we  may  safely  infer  that 
when  the  average  and  the  median  for  any  given  interval  of  the 
same  group  have  opposite  signs,  there  is  no  clear  effect  due  to 
the  filling.  The  common  result  for  these  four  modes  of  com- 
parison would  then  be  that  the  effect  of  the  filling  was  to  make 
the  time  seem  shorter  to  D  during  the  intervals  of  one,  two,  six 
and  ten  minutes.  The  two  groups  give  conflicting  results  for 
the  intervals  of  one  half  and  four  minutes,  so  that  the  position 


VISUAL  ESTIMATE  OF  TIME. 


453 


of  the  filling — whether  it  came  in  the  first  or  second  of  the  in- 
tervals—  was  the  more  important  factor.  All  four  modes  of 
comparison  agree  that  to  R  the  filled  time  seemed  longer  dur- 
ing all  intervals  except  one  half  and  one  minute.  In  these  two 
intervals  the  position  of  the  filling  is  again  the  chief  factor.  In 
the  case  of  the  third  subject,  6",  we  have  but  one  group  of  ex- 
periments. Here  the  filled  time  seemed  longer  at  one  minute 
but  shorter  at  two,  six  and  ten  minutes.  At  one  half  and  four 
minutes  there  seems  to  be  no  clear  effect  due  to  the  filling. 

It  is  evident  from  these  results  that  the  filling  does  not  affect 
all  three  subjects  alike.  In  general,  the  filled  time  seemed 
shorter  than  the  empty  to  D  and  S^  but  longer  to  7?,  though 
there  are  exceptions  in  all  three  cases. 


Table  V. 
Subject  5.    E-E. 


Interval. 

Av.  Estimate. 

■Di 

M.V.S« 

Median. 

DS< 

M.V.5( 

yi  min. 

43.6  sees. 

+  43-6 

20.4 

40.5  sees. 

+  35 

25.4 

I     " 

I  min.     6        " 

+  10 

15-7 

I  min.     2       " 

+   3-3 

27.7 

2      " 

2     "      26.4     " 

+  22 

27.7 

2     "      47       " 

+  39-1 

21.9 

4    " 

3     "      39-9     " 

-   8.3 

17.2 

3     "      47 

—   5-4 

16. 1 

6     " 

5     "      48.5     " 

—   3-1 

26.6 

6     "        2        " 

+    3.3 

24.8 

lO     " 

10     "      10.6     " 

+    1-7      15-4  1 

II     "        5 

+  10.8 

5.9 

F-E. 


Vz 

I 

2 

4 

6 

10 


I  min. 
I     " 

3  " 

4  " 


44.2  sees. 

+  47.3 

21.3 

40.9    " 

+  68.1 

15-3 

56       " 

—   3-3 

15.8 

50.4    " 

—   4 

15-4 

42.2     " 

—  18.8 

10.8 

59-1     " 

—  10. 1 

311 

I  min. 
I     " 

3  " 

4  " 
9     " 


39 

44 

55 

33-5 

22 

3-5 


ecs. 

+  30 
+  76.6 

—   4.1 

— 11.2 

—  27.2 

-  9-4 

21.5 
16 

15.9 
15 

9-4 
II. 2 


Difference  due  to  Filling. 


Average. 

Median. 

yi  min. 

+    3.7  per  eent. 

—   5 

per 

eent. 

I     " 

+  58.1 

+  73-3 

2     " 

—  25.3 

—  43-2 

4     '• 

+    4.3        " 

-   5.8 

6    " 

—  15.7 

—  30.5 

10     " 

—  11.8 

—  20.2 

The  estimates  of  empty  times  as  compared  with  empty  times, 
of  the  three  subjects,  as  shown  in  Tables  III.,  IV.  and  V.,  are 
in  all  respects  comparable.     If  we  consider  only  those  intervals 


454  MABEL  LOR  EN  A  NELSON. 

where  the  average  and  the  median  are  of  the  same  sign,  as  de- 
cisive, we  have  for  D  no  apparent  error  at  one  half  or  one 
minute,  a  positive  error  at  two  minutes,  a  negative  error  at  four 
and  six  minutes,  and  no  error  at  ten  minutes. 

The  results  do  not  show  a  constant  negative  error,  such  as 
was  found  by  Michael  Ejner  for  intervals  of  one  half,  one,  two, 
three  and  four  minutes  marked  off  by  sound.  I  found  in  taking 
the  estimates  that  when  a  short  interval  followed  a  longer  one  it 
was  in  general  lengthened.  This  fact  may  in  part  account  for 
the  overestimation  of  the  shorter  intervals. 

When  we  compare  the  estimates  of  empty  times  of  D  and 
R  with  those  of  the  first  group.  Tables  I.  and  II.,  we  find  that 
D  has  lengthened  his  estimates  in  this  second  group  (compare 
Tables  I.  and  II.).  This  change  was  not,  I  think,  due  to  prac- 
tice so  much  as  to  the  increased  strain  of  attention  demanded 
by  the  lack  of  knowledge  of  the  probable  length  of  the  stand- 
ard. R  has  decreased  the  estimate  of  one  half  minute,  and,  in 
general,  made  the  estimates  of  Table  IV.  smaller  than  those  of 
Table  II. 

For  all  intervals  longer  than  one  or  two  minutes  my  subjects 
expressed  a  dissatisfaction  with  their  estimates  and  felt  that  they 
made  little,  if  any,  difference  between  the  longer  intervals — all 
times  seeming  very  long  and  very  much  alike.  R^  at  times, 
could  not  consciously  note  any  difference  between  standards  of 
two  and  six  minutes,  or  between  those  of  four  and  ten  minutes, 
even  when  they  followed  each  other  in  close  succession,  though 
her  results  show  a  constant  and  decided  difference.  D  had 
a  better  idea ;  for,  when  asked  how  long  he  thought  an  inter- 
val had  been,  his  verbal  answer  more  nearly  approximated  the 
duration  he  had  just  marked  off  as  '  equal '  in  the  experiment. 
S  entered  the  experiments  with  a  general  knowledge  of  the 
lengths  of  time  that  were  to  be  used  as  standards,  though  igno- 
rant during  the  experiments  as  to  what  particular  one  was  being 
given  him — but  beyond  two  minutes  could  not  with  any  constancy 
identify  them  and  tell  whether  the  standards  had  been  four,  six 
or  ten  minutes. 

During  the  longer  periods  it  was  impossible  to  keep  the 
attention  so  closely  fixed  as  during  the  intervals  of  one  half  and 


VISUAL  ESTIMATE  OF  TIME.  455 

one,  or  at  most  two  minutes.  It  is  at  about  this  point  that  the 
change  of  sign  occurs  in  the  estimates.  The  general  feeling 
of  weariness  seemed  to  be  the  chief  criterion  in  the  longer  in- 
tervals. 

The  difference  due  to  the  filling  was,  I  think,  merely  a  dif- 
ference in  the  direction  of  attention,  the  monotonous  regularity 
of  the  lights  being,  in  general,  a  means  of  holding  the  attention 
and  preventing  the  mind  from  wandering.  From  this  point  of 
view  the  filled  time  was  psychologically  the  more  empty  or 
barren  of  the  two — the  time  being  filled  with  monotonous  sensa- 
tions of  light,  but  empty  of  vivid  or  interesting  trains  of  thought. 
In  looking  back  over  it,  then,  there  would  be  fewer  changes  in 
consciousness  to  remember,  and  hence  the  time  would  seem 
shorter.  This  would  be  in  keeping  with  the  fact  that  the  in- 
creased mental  activity  produced  by  certain  narcotic  drugs 
makes  time  seem  long ;  the  person,  on  recovery,  remembering 
the  vast  number  of  his  experiences,  overestimates  the  time. 

What  is  the  result  of  these  experiments  as  compared  with 
Dr.  Meumann's,  and  with  the  space  illusions  of  sight  and  touch? 
"We  find  that  in  sight  a  space  is  overestimated  when  it  is  filled ; 
an  interrupted  line  will  seem  longer  than  a  continuous  one,  a 
line  divided  into  more  than  two  parts  longer  than  an  undivided 
one  of  the  same  length.  In  touch,  while  an  interrupted  line 
of  lo  mm.  is  underestimated,  yet  a  longer  one,  lo  cm.,  will  be 
overestimated  when  it  is  interrupted.*  Whether  the  effect  of 
the  filling  in  these  time  intervals  corresponds  to  that  in  the 
space  illusions  would  depend  on  which  of  the  two  times  we  con- 
sider to  be  the  filled ;  for,  in  these  long  intervals  the  sensations 
of  light  have  but  an  indirect  influence,  and  are  not  the  only  fill- 
ing, nor  the  chief  factor  in  the  appreciation  of  time.  Taking 
it,  however,  as  ordinarily  understood,  we  do  not  find  here  a 
constant  negative  error  such  as  Dr.  Meumann  found  in  his  long- 
est times,  although  to  two  of  the  subjects,  D  and  S,  the  filled 
time  in  general  seemed  shorter. 

The  results  of  the  third  subject,  7?,  are  more  in  accord  with 
the  space  illusion  of  sight,  and  of  touch  when  the  standard  is 
one  of  lo  cm. — the  filling  making  the  stretch  seem  longer. 

^  See  the  accompanying  paper  by  Miss  Robertson,  already  referred  to. 


456 


MABEL  LOR  EN  A  NELSON. 


To  test  the  question  as  to  the  effect  of  single  and  multiple 
divisions  of  time,  and  to  determine  whether  in  the  temporal  esti- 
mate there  was  anything  like  the  space  error  in  vision,  where 
halving  produces  a  negative  error  and  more  divisions  a  positive 
one,  visual  intervals  of  3,  6,  12,  18,  30  and  60  seconds  were,  by 
the  same  method  as  that  described  above,  divided  into  halves, 
thirds  and  fourths. 

Under  each  interval  ten  estimates  were  taken  for  an  empty 
time,  and  ten  for  each  character  of  filling,  on  each  of  two  sub- 
jects. A  pause  of  two  seconds  was  made  between  the  standard 
and  the  compared  time,  the  compared  time  being  here  always 
empty.  In  order  that  the  subjects  might  know  when  the  end 
of  the  standard  had  arrived,  the  word  'now'  was  spoken  im- 
mediately after  the  last  flash  of  the  standard.  A  stop-watch 
measuring  two  tenth  seconds  was  used  by  the  experimenter  to 
mark  off  the  estimate.  Although  there  was  a  reaction  error 
here,  yet  it  was  common  to  both  sets  of  experiments  alike,  and 
•so  might  be  neglected  in  comparing  them. 


Table  VI. 
Subject  R. 


Interval. 

No.  of  Lights. 

Average. 

M.  V.i 

Median. 

M.  v.  i 

3  sees. 

2 

3-94 

10 

4 

9 

3 

4.24 

24 

4 

25 

4 

4.71 

15 

4.7 

14 

6     " 

2 

6.28 

16 

6 

16 

3 

6.88 

20 

6.5 

20 

4 

8.82 

16 

8.4 

16 

5 

8.80 

15 

9.2 

14 

12     " 

2 

10.62 

17 

9.8 

17 

3 

10.96 

13 

10.4 

10 

4 

12.88 

9 

12.2 

9 

5 

13.38 

8 

13-8 

7 

18     " 

2 

13-24 

16 

13 

15 

3 

13.46 

22 

13.3 

21 

4 

16.44 

13 

17-3 

12 

5 

14.10 

9 

13-6 

8 

30     " 

2 

20.04 

16 

19. 1 

17 

3 

20.22 

23 

19 

20 

4 

19.66 

20 

16.6 

29 

5 

24.58 

26 

23.9 

22 

60     " 

2 

32.84 

26 

28.7 

26 

3 

35.90 

35 

30.9 

37 

4 

39-76 

19 

40.1 

19 

5 

35-56 

19 

32.7 

16 

VISUAL  ESTIMATE  OF  TIME. 

Table  VII. 
Subject  Rd. 


457 


Interval. 

No.  of  Lights. 

Average. 

M.  V.  5f 

Median. 

M.  V.f, 

3  sees. 

2 

3-74 

19 

3-8 

18 

3 

4-56 

13 

4.5 

13 

4 

4.28 

10 

4.4 

10 

6     " 

2 

4.80 

8 

4.8 

6 

3 

6.68 

17 

6.9 

16 

4 

7-44 

16 

7-1 

15 

5 

8.36 

12 

8.7 

12 

12     " 

2 

10.07 

14 

10 

14 

3 

10.34 

19 

9-3 

20 

4 

II. II 

22 

9-9 

22 

5 

11.48 

16 

11.6 

16 

i8     " 

2 

11.05 

12 

10.3 

14 

3 

13-83 

II 

14-35 

9 

4 

12.76 

14 

13-8 

II 

5 

15-35 

12 

15-3 

10 

30  '« 

2 

17.41 

14 

16.3 

14 

3 

18.17 

13 

17-75 

13 

4 

17.99 

18 

16.35 

16 

5 

18.63 

II 

19.4 

16 

60   " 

2 

30.64 

12 

30.4 

II 

3 

34-56 

16 

34.3 

17 

4 

30.71 

II 

29.9 

II 

5 

33-54 

17 

34.2 

16 

The  result  we  find  (see  Tables  VI.  and  VII.)  is  that  whether 
the  average  or  the  median  be  taken  as  the  basis  for  comparison, 
the  empty  time  seemed  shorter  than  the  filled,  and,  in  general, 
the  time  seemed  longer  as  the  number  of  impressions  was  in- 
creased. For  the  three  longer  periods  —  eighteen,  thirty  and 
sixty  seconds  —  the  standard  when  divided  into  halves  seemed 
longer  than  when  divided  into  thirds  to  Rd ;  while  to  R  the 
standard  when  divided  into  thirds  seemed  longer  than  when 
divided  into  fourths,  during  the  intervals  of  eighteen  and  sixty 
seconds. 

It  is  probable  that  in  these  longer  periods  the  attention  is  not 
held  closely  to  the  sensations  of  light,  so  that  other  factors  play 
a  greater  part  in  determining  the  estimate.  In  the  shorter  in- 
tervals, however,  the  mind  can  be  kept  relatively  empty,  so 
that  the  sensuous  filling  is  the  chief  measure  of  duration.  As 
long  as  the  attention  could  be  concentrated  on  the  sensations, 
the  number  of  lights  would,  I  think,  affect  the  estimate.  Cases 
where  in  the  present  experiments  the  standard  was  subdivided 


45^  MABEL  LORENA  NELSON. 

into  thirds  could  always  be  consciously  distinguished  from  those 
divided  into  halves,  but  many  times  where  the  standard  was 
divided  into  fourths  it  could  not  be  distinguished  from  thirds ; 
more  than  fourths,  I  feel  sure,  could  not  have  been  appre- 
hended without  counting. 

From  these  results  we  would  say  that  in  relatively  short 
times  as  well  as  in  spaces,  the  estimate  is  influenced  by  the 
number  of  impressions  that  fall  within  the  stretch.  There  is  no 
evidence  whatever  of  a  shortening  up  of  the  estimate  due  to  the 
division  of  the  standard  into  halves,  such  as  is  found  in  vision. 

With  Rd  the  division  of  the  standard  into  fourths  always 
gives  a  greater  estimate  than  the  division  into  thirds,  but  the 
estimate  of  thirds  is  often  less  than  that  of  halves.  7?,  with 
but  three  exceptions,  increases  the  estimate  as  the  number  of 
divisions  increases. 

We  find  a  great  similarity  in  the  absolute  durations  given  in 
the  estimate  of  the  two  subjects.  Practice  on  longer  intervals 
does  not  enable  R  to  judge  these  shorter  intervals  any  more 
accurately  than  Rd^  who  had  no  former  practice,  nor  does  it 
tend  to  reduce  the  variation ;  this  being  as  large  as  in  the 
former  experiments  and  somewhat  larger  than  that  of  Rd. 

The  position  of  the  indifference  point  —  where  there  is  no 
absolute  over-  or  underestimation  —  lies  with  both  R  and  Rd 
between  six  and  twelve  seconds.  The  overestimation  of  three 
and  six  seconds  may  be  due  to  assimilation  with  longer  inter- 
vals. This  would  correspond  with  the  results  of  Estel,^  who 
found  that  an  interval  of  three  seconds,  when  it  followed  one  of 
two  seconds,  seemed  shorter  than  when  it  followed  one  of  four 
seconds.  This  would  also  explain  the  shortening  up  of  the  esti- 
mates of  empty  intervals  of  thirty  and  sixty  seconds  in  the  case 
of  subject  R  as  compared  with  her  former  estimates  given  in 
Tables  II.  and  IV. 

As  a  final  result  of  these  experiments  we  find,  in  intervals 
of  time  ranging  from  three  to  sixty  seconds,  evidence  of  a  tem- 
poral illusion  very  similar  to  the  space  illusion  of  sight.  Both 
in  time  and  in  visual  space,  when  there  is  more  than  a  single 
division,  the  filled  stretch  is  overestimated.     We  do  not  find, 

^ Philosophische  Studien,  II.,  p.  55. 


VISUAL  ESTIMATE  OF  TIME.  459 

however,  that  a  single  division  shortens  up  the  temporal  estimate. 
This  is  in  keeping  with  the  space  illusion  of  touch  when  the 
standard  is  lo  cm.,  but  opposed  to  Dr.  Meumann's  results,  as 
he  finds  intervals  from  four  to  nine  seconds  are  underestimated 
when  a  single  division  is  used. 

As  we  increase  the  length  of  the  standard  interval  to  min- 
utes, we  do  not  get  a  direct  reversal  of  the  effect  of  the  filling 
such  as  is  found  in  touch ;  but  we  find  the  illusion  either  de- 
creases or  is  entirely  lost. 


linWtj  of  California 

i^liolaglcal  Laboratoiy. 


4 


REPRINTED  FROM 

VOL  IX.    No.  6.  November,  1902. 

THE 

Psychological  Review 

EDITED  BY 
J.  McKEEN  CATTELL  J.  MARK  BALDWIN 

Columbia  University  Princeton  University 

WITH  THE  CO-OPERATION  OF 
ALFRED  BINET,  Ecole  des  Hautes-Studes,  Paris;  JOHN  DEWEY,  H.  H.  DONALD- 
SON, University  of  Chicago  ;  G.  S.  FULLERTON,  University  of  Pennsylvania  ; 
G.  H.  HOWISON,  University  of  California;  JOSEPH  JASTROW,  Uni- 
versity OF  Wisconsin;    G.  T.   LADD,  Yale    University;    HUGO 
MONSTERBERG,  Harvard  University;  M.  ALLEN  STARR, 
College  of  Physicians  and  Surgeons,  New  York  ;  CARL 
STUMPF,  University,  Berlin  ;   JAMES  SULLY, 
University  College,  London. 

H.  C.  WARREN,  Princeton  University,  Associate  Editor  and  Business  Manager. 


STUDIES    FROM   THE    PSYCHOLOGICAL    LABORATORY 
OF   THE   UNIVERSITY   OF   CALIFORNIA. 

COMMUNICATED!  BY   PROFESSOR   GEORGE   M.    STRATTON. 

VI.     '  Geometric-Optical'  Illlusions  in  Touch. 

BY   DR.   ALICE   ROBERTSON. 


PUBLISHF.D    BI-MONTHLY    BY 

THE  MACMILLAN  COMPANY, 

41  N.  QUEEN  ST.,  LANCASTER,  PA. 

66    FIFTH    AVENUE,    NEW    YORK. 

Agent:  G.   E.  STECHERT,  London  (2  Star  Yard,  Carey  St.,  W.  C.) 

Leipzig  (Hospital  St.,  10);    Paris  (76  rue  de  Rennes). 


Ibteslif  of  IJaiWa 


[Reprinted  from  The  Psychological  Review,  Vol.  IX.,  No.  6,  Nov.,  1902.] 


STUDIES   FROM   THE   PSYCHOLOGICAL   LABORA- 
TORY OF  THE  UNIVERSITY  OF  CALIFORNIA. 

COMMUNICATED   BY  PROFESSOR   GEORGE   M.   STRATTON. 

VI.     'Geometric-Optical'  Illusions  in  Touch. 

BY  DR.    ALICE  ROBERTSON. 

The  interest  which  attaches  to  experiments  upon  the  so- 
called  'geometric-optical'  illusions,  viz.,  the  investigation  of 
our  perception  of  space,  is  not  lessened  when  the  investigation 
is  carried  into  the  tactual  field.  The  experiments  recorded  in 
the  following  pages  constitute  an  attempt  to  investigate,  by 
touch  alone,  certain  geometrical  figures  which  present  well- 
known  optical  illusions.  Since  sight  and  touch  are  so  closely 
related,  and  since  our  theories  of  space  perception  are  based  in 
the  main  upon  optical  phenomena,  the  following  observations 
may  serve  to  test  some  of  these  theories.  For  example,  from  his 
study  of  reversible  perspective,  Thiery^  arrives  at  the  conclu- 
sion that  all  optical  illusion  is  due  to  the  perspective  in  any 
given  figure,  whether  consciously  or  unconsciously  perceived. 
According  to  this  observer,  the  convergence  or  divergence  of 
lines  produces  in  us  an  effect  of  depth,  or  of  foreshortening,  so 
that  small  angles  are  only  larger  ones  interpreted  perspectively, 
and  an  object  seen  near  the  apex  of  an  angle  seems  larger  than 
one  at  its  opening,  because  it  appears  to  be  further  away,  and 
we  connect  distance  with  larger  size.  It  is  obvious  that  the 
tactual  perception  of  plane  figures,  the  mere  contact  of  the  fin- 
gers or  of  the  hand  upon  any  part  of  a  flat  surface,  can  produce 
no  effect  of  perspective.  When,  however,  it  is  found  that  illu- 
sion remains,  serious  doubt  is  cast  upon  the  importance  of  per- 
spective, even  in  the  sight  illusion. 

In  considering  what  figures  are  suitable  for  experimentation 
in  the  tactual  field,  it  is  clear  that  not  all  figures  which  pro- 

^  Phil.  Stud.,  XI.,  pp.  307  and  603,  XIL,  p.  67. 

549 

Mmii]  of  U\\m 

Psyfiiioiogical  Laboratoni. 


55°  ALICE  ROBERTSON. 

duce  an  effect  upon  sight  can  be  used.  Simple  figures,  those 
containing  but  few  lines,  are  best  adapted  to  this  purpose.  If 
the  figure  is  composed  of  many  lines,  a  blur  of  sensations  is 
received,  and,  as  would  be  said  in  microscopy,  it  is  difficult  to 
get  a  sharp  definition.  The  apparatus  which  was  used  in  the 
following  experiments  consisted  of  black  cardboard  in  which 
the  figures  were  pricked  with  a  fine  cambric  needle,  the 
prickings  being  placed  so  close  together  that  they  could  not 
tactually  be  distinguished  as  separate  points.  Or,  in  a  few 
cases,  the  shape  of  the  figure  to  be  experimented  with  was  made 
by  pasting  narrow  strips  upon  a  larger  piece  of  cardboard,  and 
this  outline  was  either  explored  by  the  tips  of  the  fingers,  or  the 
hand  as  a  whole  was  passed  over  the  figure. 

Throughout  these  experiments,  active  touch  has  been  em- 
ployed. The  rapidity  of  movement,  the  amount  of  pressure  ex- 
erted, and  the  portion  of  the  hand  which  received  the  sensation, 
make  marked  differences  in  some  cases  in  the  amount  of  illu- 
sion. Sometimes  an  illusion  which  existed  in  a  very  marked 
degree  when  the  hand  as  a  whole  was  passed  over  the  figure, 
became  almost  inappreciable  if  the  finger-tips  were  freely  used 
to  explore  the  contour.  In  other  cases  the  illusion  remained 
whichever  method  was  adopted.  As  a  rule,  the  hand  has  been 
passed  rather  lightly  and  somewhat  rapidly  over  the  figure,  and 
the  judgment  has  been  recorded  either  in  words  or  in  a  drawing 
of  the  object  as  it  was  perceived  by  the  tactual  sense. 

The  agreement  or  divergence  between  the  illusions  of  touch 
and  of  sight  afford  a  wide  basis  of  classification  for  the  experi- 
ments here  described.  In  very  few  cases  only  can  the  tactual 
illusion  be  said  to  be  merely  in  the  same,  or  in  a  reverse  direc- 
tion from  that  which  is  found  in  sight.  Other  phenomena  of 
illusion  also  appear,  e.  g.^  illusions  of  curvature  where  lines  are 
straight,  or  illusions  of  greater  length  or  height  where  no  dif- 
ference exists  in  reality.  Generally  speaking,  however,  the 
whole  set  of  experiments  is  divisible  into  two  classes.  The 
first  includes  those  figures  in  which  the  illusion  follows  the 
same  direction  as  that  of  sight.  The  second  includes  those  fig- 
ures which  afford  an  illusion  in  the  opposite  direction.  Other 
phenomena  connected  with  these  figures  will  be  noticed  in  the 
description. 


GEOMETRIC-OPTICAL  ILLUSIONS  IN  TOUCH.  55 1 

Class  I. 

The  experiments  which  fall  under  the  first  class  consist  of  a 
miscellaneous  group  of  minor  illusions  which  are  common  and 
well  known  in  the  field  of  sight.  The  purpose  has  not  been  to 
make  a  complete  investigation  of  the  phenomena  revealed  here, 
but  merely  to  find  out  whether  illusion  exists,  and,  if  so,  to  what 
extent  it  resembles  the  visual  phenomena.  These  figures  were 
presented  from  time  to  time  to  several  subjects,  no  attempt  being 
made,  except  in  one  or  two  cases,  to  vary  the  conditions. 

I.  Milller-Lyer  Illusion. — In  this  well-known  figure  a 
marked  tactual  illusion  exists.  For  purposes  of  experiment  the 
oblique  lines  at  the  extremities  of  the  horizontals  were  not  joined 
close  to  the  latter.  Space  enough  was  left  so  that  the  ends  of 
the  horizontals  could  be  distinctly  felt.      In  every  case  illusion 


/ 


/ 

A 

\ 

X 

\ 

B 

Fig.  I.  Fig.  2.  Fig.  3. 

in  regard  to  the  length  of  the  line  was  very  apparent.  It  was  in 
the  same  direction  as  that  found  in  sight,  but  greatly  intensified. 
That  is,  when  compared  by  the  sense  of  touch  alone,  A  (Fig. 
i)  seemed  not  only  longer  than  B,  but  the  difference  in  length 
between  them  seemed  much  greater  than  appears  to  sight. 

2.  Illusion  of  Convergent  Lines. — Experimentation  upon  a 
suitable  figure  of  the  pattern  represented  in  the  drawing  gave 
perfectly  definite  and  unvarying  results.  When  the  hand  is 
passed  over  the  figure  and  the  sizes  of  the  two  circles  are  com- 
pared, that  one  {A)  which  is  in  the  apex  of  the  angle  seems  the 
larger  —  a  result  similar  to  that  which  is  found  in  sight. 
The  result  in  question  seems  to  be  due  to  a  blending,  to  a  cer- 
tain degree,  of  the  sides  of  the  angle  with  the  periphery  of  the 
circle  and  an  interpretation  of  this  as  meaning  that  the  circle  A 
is  larger  than  B^  B  being  relatively  uninfluenced  by  the  lines 


552  ALICE  ROBERTSON. 

near  it.  If  this  be  true,  then  the  apparent  size  of  A  relative 
to  B  should  change  with  a  change  in  its  position  relative  to  the 
apex  of  the  angle.  This  supposition  seems  to  be  confirmed  by 
a  few  experiments  conducted  for  the  purpose  of  testing  it. 

3.  Perception  of  Angles. — In  the  optical  illusion  presented 
by  Fig.  3,  the  circle  seems  to  be  flattened  somewhat  where  it 
touches  the  corners  of  the  square,  while  the  sides  of  the  latter 
are  very  slightly  bent  inward.  The  same  phenomena  greatly 
accentuated  appear  also  in  the  tactual  illusion.  In  experiment- 
ing with  this  figure,  subjects  were  requested  not  to  explore  the 
contour  with  the  figure-tips.  A  record  of  the  impression  received 
by  passing  the  hand  back  and  forth  over  the  figure  as  a  whole, 
was  made  in  drawing  by  each  subject,  and  samples  of  the  data 
obtained  from  two  subjects,  S  and  TV",  are  given  below  (Figs. 
4  ''ind  5). 

Fig.  4  represents  the  impression  which   subject  S  received 


Fig.  4.  Fig.  5.  Fig.  6. 

when  the  hand  was  passed  over  the  figures  as  a  whole  in  any 
direction.  The  sides  of  the  square  curved  inward,  and  the 
periphery  of  the  circle  seemed  to  be  divided  into  distinct  seg- 
ments, which  flattened  very  much  as  their  extremities  ap- 
proached the  corners  of  the  square. 

Fig.  5  represents  the  impression  received  by  subject  iV^  of 
the  same  figure.  In  this  case  the  hand  was  passed  from  right 
to  left  or  vice  vcisa  across  the  figure  as  a  whole,  at  which  time 
the  square  lengthened  horizontally,  the  shorter  sides  only  seem- 
ing to  curve  slightly  inward.  The  circle  seemed  to  be  an 
ellipse  somewhat  flattened  at  the  corners  of  the  inner  rectangle. 
When  the  figure  was  turned  through  45°,  and  the  hand  was 
moved  as  before  from  right  to  left  and  back  again,  then  the 
square  became  a  flattened  diamond  shape,  and  the  circle  an 
ellipse  somewhat  flattened  at  the  corners  of  the  inclosed  figure 


GEOMETRIC-OPTICAL  ILLUSIONS  IN  TOUCH. 


553 


(Fig.  6.)  To  this  subject,  '  horizontal '  distances,  that  is,  dis- 
tances right  and  left,  seem  distinctly  longer  than  equal  vertical 
ones.  Also,  the  upper  part  of  a  figure  which  is  felt  by  the  hand 
as  a  whole,  usually  seems  higher  and  more  distinct  than  the 
lower  part  of  a  symmetrical  figure.  Thus,  in  the  two  positions 
recorded  above  (Figs.  5  and  6)  the  curve  of  the  ellipse  is  higher 
above  than  below,  as  is  also  the  point  of  the  diamond  in  Fig.  6. 
4.  Illusions  of  Contour. — A  tactual  illusion  similar  to  that 


Fig.  7. 


Fig.  8. 


which  is  found  in  sight  appears  also  when  the  hand  is  passed 
over  two  semicircles,  the  one  closed  and  the  other  open,  as 
represented  in  the  drawing  (Fig.  7).  In  this  case  the  arc  of 
the  open  semicircle  seems  to  flatten  out  and  to  become  the  arc 
of  a  larger  circle.  Besides  this  illusion  in  contour  another  one 
appears  in  A  which  is  not  observed  in  sight.  When  the  con- 
tour of  A  is  perceived  by  the  hand  as  a  whole,  the  first  impres- 
sion is  that  of  a  figure  composed  of  two  curves,  one  of  which  is 
flatter  than  the  other  (Fig.  8).  The  curve  of  the  arc  of  the 
circle  seems  to  impress  itself  upon  the  chord  and  it  appears  to 
bulge  slightly. 

Similarly,  if  the  two  squares  A  and  B  (Fig.  9)  are  compared 
in  the  manner  above  described  for  the  semicircles,  the  open 
figure  B  will  seem  the  larger.  In  some  cases  A  is  felt  as  a 
square,  ^  as  a  rectangle  whose  longer  sides  are  horizontal. 
In  other  cases  both  A  and  B  seem  to  be  lengthened  rectangles, 
B  seeming  the  longer  of  the  two.  In  the  comparison  of  the 
semicircles  and  of  the  squares,  the  illusion  in  each  case  corre- 
sponds to  what  we  find  in  sight,  and  probably  for  a  similar  rea- 
son, viz.,  the  inclusion  within  the  figure  of  some  of  the  outside 
free  space. 


554 


ALICE  ROBERTSON. 


5.  Ring  Segments. — When  the  two  segments  (Fig.  10), 
which  are  objectively  equal,  are  compared  by  touch,  an  illusion 
similar  in  direction  to  that  of  sight  is  very  evident.  Not  only  is 
a  tactual  illusion  apparent  when  the  segments  are  objectively 
equal,  but  also  when  the  upper  segment  is  actually  larger  than 
the  lower,  and  when  to  sight  no  illusion  whatever  exists.  That 
is,  it  is  found  by  experimentation  that,  if  two  segments  are  com- 
pared in  which  the  inner  curve  of  the  upper  segment  is  equal  to 
the  upper  curve  of  the  lower  (Fig.  11),  a  tactual  illusion  is 
apparent  in  a  larger  number  of  cases.  In  Fig.  10,  80^  of  the 
judgments  obtained  from  five  persons  were  in  accord  with  the 
ordinary  visual  illusion,  that  is,  A  seemed  smaller  than  B.  At 
the  same  time,  in  the  other  20^  of  the  judgments,  A  was  con- 


A 


B 


Fig.  9. 


sidered  either  larger  or  equal  to  B,  or  the  subject  was  in  doubt. 
The  evidence  for  illusion  in  this  figure  is  by  no  means  so  conclu- 
sive, so  unvarying  in  its  effect  on  the  tactual  sense,  as  it  is  in 
vision.  On  the  other  hand,  it  is  remarkable  that  in  the  unequal 
segments  represented  in  Fig.  11,  so  large  a  percentage  of  judg- 
ments should  give  evidence  of  a  tactual  illusion.  The  larger 
size  of  A  in  Fig.  11  is  very  evident  to  the  eye,  yet  when  the 
comparison  is  made  by  touch,  in  42^  of  the  judgments  A  is 
considered  smaller  or  equal  in  size  to  B.  If  the  cards  are 
turned  at  right  angles,  and  the  segments  are  compared  in  this 
position,  the  errors  in  judgment  are  increased.  In  the  case  of 
Fig.  10,  the  increase  is  not  large,  81^  of  the  judgments  are  in 
favor  of  the  smaller  size  of  A,  while  for  Fig.  11,  56^  of  the 
judgments  are  that  A  is  either  smaller  than  B  or  equal  to  it. 
The  error  in  these  figures  seems  to  indicate  that  the  tactual 
comparison  of  the  two  segments  becomes  a  comparison  of  the 
lengths  of  the  two  more  closely   approximated  curves,  rather 


GEOMETRIC-OPTICAL  ILLUSIONS  IN  TOUCH. 


555 


than  a  comparison  of  the  size  of  the  segments  as  a  whole. 
This  is  thought  to  be  the  reason  why  an  increase  of  errors 
occurs  when  the  cards,  and  consequently  the  segments,  are 
turned  at  right  angles  to  the  positions  represented  in  Figs.  lO 
and  II.  In  this  position  the  oblique  sides  of  the  segments  are 
brought  directly  under  the  fingers,  and  hence  come  into  more 
prominent  notice.  The  tips  of  the  fingers  naturally  follow  the 
slanted  edge  of  the  upper  or  right-hand  segment,  and  thus  they 
are  brought  some  distance  within  the  slanted  edge  of  the  lower, 
or  left-hand  segment,  and  the  former  is  considered  the  smaller. 


A 


In  each  of  the  preceding  figures  certain  tactual  illusions  oc- 
cur which  are  in  the  same  direction  as  those  which  appear  to 
the  eye  and  which  seem  analogous  to  the  optical  illusions.  As 
has  been  said,  these  optical  phenomena  have  been  ascribed  to 
perspective  as  the  primary  cause ;  but  in  the  experiments  here 
presented  perspective  cannot  enter,  and  yet  the  results  are  the 
same.  While  it  does  not  necessarily  follow  that  the  phenomena 
of  sight  and  touch  should  be  referred  to  the  same  cause,  yet  the 
results  here  obtained  are  thought  to  diminish  the  force  of  per- 
spective as  a  fundamental  cause  of  illusion  even  in  sight. 


556  ALICE  ROBERTSON. 

Class  II. 

I.  A  ^lantitative  Comfai-ison  of  Lines  of  a  Varying  Num- 
ber of  Interruptions  with  an  Uninterrupted  Line  of  Standard 
Length. — The  experiment  here  described  is  intended  to  investi- 
gate the  phenomena  which  appear  when  lines  variously  inter- 
rupted are  compared,  by  the  sense  of  touch  alone,  with  an  unin- 
terrupted line.  The  results  show  a  reversal  of  the  illusion  which 
appears  in  the  visual  field,  and  instead  of  an  overestimation  of 
the  interrupted  extents  such  as  takes  place  in  vision,  there  is 
underestimation,  i.  e.,  the  interrupted  lines  seem  shorter  than 
they  actually  are. 

The  apparatus  which  was  used  consisted  of  a  number  of 
cards,  made  of  black  cardboard,  27  cm.  long  by  13  cm.  wide, 
in  the  center  of  which  the  lines  were  pricked.  Four  kinds  of 
lines  were  used.     First,  a  plain,  uninterrupted,  smoothly  pricked 

line  ( ).     Secondly,  a  line  similar  to  the  preceding 

but  having  its  extremities  defined  by  a  short  line  at  right  angles 

(  I I ).     Thirdly,  a  line  defined  at  each  extremity  by 

cross  lines    and  also   divided   in   the   middle   (  | 1 1 ) ; 

and  fourthly,  a  line  divided  in  a  similar  manner  into  sixths 
(  I— I— i— I— I— I— I  )•  The  cards  thus  fall  into  four  groups,  each 
group  consisting  of  a  series  of  lines  varying  in  length  from  7 
cm.  to  15  cm.  The  lines  varied  by  steps  of  5  mm.  throughout 
that  portion  of  the  series  where  the  difference  was  actually 
found  to  be  difficult  to  perceive.  The  lengths  of  the  lines  com- 
posing a  series,  then,  were  as  follows:  7,  8,  9,  9.5,  10,  10.5, 
II,  II. 5,  12,  12.5,  13,  14,  15  centimeters.  The  standard  line 
with  which  all  comparisons  were  made,  was  a  plain  unbroken 
line  ( )  ten  centimeters  in  length. 

In  conducting  the  experiment  the  subject  was  seated  with 
closed  eyes  before  a  table  of  convenient  height,  upon  which  his 
whole  arm  rested  comfortably.  The  standard  card  was  first 
presented  to  him,  and  then  the  other  cards  of  any  particular  set, 
one  after  the  other,  were  laid  below  it  for  his  comparison.  He 
was  permitted  to  pass  the  hand  back  and  forth  from  the  card  to 
be  compared  to  the  standard,  and  vice  versa,  as  often  as  he 
pleased  before  he  gave  his  judgment.  The  right  hand  was 
always  used,  and  no  restrictions  were  placed  upon  him  as  to 


GEOMETRIC-OPTICAL  ILLUSIONS  IN  TOUCH. 


557 


what  part  of  the  hand  should  receive  the 
stimulation.  Sometimes  the  tips  of  the 
fingers  alone  were  used,  again  the  por- 
tion of  the  hand  just  below  the  finger- 
tips. In  giving  a  judgment  the  subject 
was  asked  to  state  whether  the  line 
seemed  longer  or  shorter  than  the  stand" 
ard  or  equal  to  it.  A  series  consisted  of 
an  ascending  and  descending  portion, 
and  an  equal  number  of  each  began 
with  the  shortest  line  and  proceeded 
gradually  to  the  longest,  and  vice  versa. 

Ten  such  double  series  were  obtained 
from  each  of  three  subjects,  B^  S  and 
JY,  the  results  of  which  are  shown  in 
Table  I.  As  a  matter  of  fact,  series 
were  obtained  from  many  more  persons* 
and  the  results  in  many  cases  were  much 
more  striking  than  those  which  are  here 
presented.  The  experiments  here  re- 
corded are,  however,  in  every  way  the 
most  systematic  and  trustworthy.  In 
the  table  each  value  for  the  upper  (U.  T.) 
and  lower  (L.  T.)  threshold  is  an  aver- 
age of  twenty  single  determinations,  and 
the  equality  point  (E.  P.)  and  mean  vari- 
ation (M.  V.)  are  an  average  of  forty  de- 
terminations. 

Examination  of  the  table  of  thres- 
holds shows  much  individual  variation 
in  the  ability  to  estimate  the  differences 
between  the  various  lines.  All  show  un- 
derestimation, that  is,  the  line  which  is 
compared,  when  really  equal  to  a  stand- 
ard, seems  shorter  than  the  standard, 
even  in  Group  I.  There  seems  to  be 
much  difficulty  for  all  subjects  to  discrim- 
inate in  the  case  of  this  group.     In  the 


w 
< 


O 
to 

P4 

D 
O 

as 

o 

o 

w 
w 

o 
to 

12; 
o 

M 
< 

< 
> 

< 
w 


< 
trt 

O 
hJ 

o 

w 

rt 
W 
Oi 
W 
H 

< 

O 

< 

H 

o 
w 

<! 

H 


rrjcOOO 

a 

3 
0 

u 

0 

- 

POM     10 

M  cJ  d 

M    IH     HI 

4 

NOO    IT) 

M  M  0 
M     M     M 

t3 

M  N  pi 

M     M     M 

0. 

3 

2 
0 

- 

- 

> 

00  t^  t^ 
PI   rO  CO 

to 

II. 2 
II.8 
II. 2 

4 

II. 2 
II. 6 
II. 2 

t3 

CO  >H  PI 
M     N     M 

H     M     M 

M 
l-( 

P. 

3 

2 

0 

PI  Tf  fo 

to" 
w 

oqvo  t^ 

d  w  t-l 

M     W    M 

l-j- 

00         t^ 

0  M  M 
M     M     W 

ONfOoo 
d  pi  M 

M    W     M 

M 
P. 

3 
0 

0 

> 

PI  >*  0 
-     PI    Tt- 

to 
W 

d  M  d 

M     M     M 

rtOO  VO 

d  d  d 

HH     h-t     W 

i^ 
tJ 

d  w  d 

M     M     M 

QClCo^ 

55 S  ALICE  ROBERTSON. 

cases  here  reported  one  subject,  S,  shows  an  underestima- 
tion amounting  to  i  cm.,  the  other  two  subjects  each  aver- 
age about  one  half  a  centimeter  of  error.  The  amount  of 
error  in  the  case  of  subject  S  is  always  large,  but  increases 
at  an  even  rate  with  the  number  of  interruptions,  so  that  the 
line  with  the  greatest  number  of  interruptions  seems  in  his 
case  to  be  the  shortest.  For  subject  B  the  amount  of  un- 
derestimation is  somewhat  less  in  each  case,  but  it  proceeds  at 
the  same  even  pace,  and  a  line  much  divided  seems  shorter 
than  one  objectively  equal  but  undivided.  The  case  is  some- 
what different  for  N.  For  this  subject  the  effect  of  the  limit- 
ing lines  at  the  extremities  in  Group  II.  is  marked  by  a  sudden 
increase  in  the  amount  of  underestimation.  The  compared  line 
in  Group  II.  seems  to  be  shortest  of  all,  while  the  compared 
lines  in  Groups  III.  and  IV.  relatively  lengthen.  But  even 
with  this  subject  the  line  containing  the  greater  number  of  in- 
terruptions is  equal  to  the  uninterrupted  line  and  not  longer,  as 
is  the  case  in  sight. 

From  the  data  furnished  by  these  experiments,  we  may  con- 
clude that  when  a  line  ten  centimeters  in  length,  definitely 
marked  at  its  extremities,  and  with  or  without  interruptions  in 
its  length,  is  compared  with  a  plain  unbroken  line  objectively 
equal  to  it,  it  appears  shorter  to  the  tactual  sense,  or  is  un- 
derestimated. In  general,  this  result  agrees  with  the  conclu- 
sion at  which  Professor  Parrish  ^  arrived  in  his  investigation  of 
similar  phenomena  with  passive  touch.  He  used  lines  64  mm. 
long,  all  being  marked  at  their  extremities  and  variously  inter- 
rupted in  their  extents.  He  considers  that  the  results  which  he 
obtained  clearly  point  to  a  reversal  of  the  optical  phenomena. 
Dr.  Dresslar,^  on  the  other  hand,  concludes  from  experiments 
which  he  conducted  with  both  active  and  passive  touch,  that  the 
tactual  illusion  follows  the  same  direction  as  the  illusion  of 
sight.  A  study  of  the  data  of  the  latter's  experiments,  how- 
ever, given  in  Tables  I.  and  II.,  pp.  334,  335,  of  his  article, 
suggests  that  perhaps  a  transition-point  from  under-  to  overesti- 
mation  may  be  found  in  them,  between  the  long  and  the  short 

^  Amer.  Jotir.  of  Psy.,  VI.,  p.  514. 
^  Amer.  Jour,  of  Psy.,  VI.,  p.  314. 


GEOMETRIC-OPTICAL  ILLUSIONS  IN  TOUCH.  559 

interrupted  intervals.  Certainly  in  Table  II.,  in  which  the  judg- 
ments are  given  upon  longer  lines  (5  to  16  cm.),  there  is  a  de- 
cided falling  off  of  the  relative  number  of  judgments  in  favor 
of  the  greater  length  of  the  filled  space.  Indeed,  the  writer 
himself  remarks  on  page  337,  that  '  when  the  spaces  to  be  com- 
pared are  more  than  10  cm.  in  length,  the  illusion  does  not  hold 
so  steadily.'  In  fact,  from  about  10  cm.  on,  the  illusion  tends 
to  take  the  opposite  direction  from  that  which  appeared  below 
that  length  and  from  that  which  appears  in  the  visual  field. 

From  the  results  of  a  few  tentative  experiments  upon  short 
interrupted  intervals,  an  analogy  between  our  sensations  of 
touch  and  our  perception  of  time  is  suggested.  It  is  well 
known  that  time  of  a  given  length,  but  interrupted  at  regular 
intervals,  seems  within  certain  limits  to  be  shorter  than  an  equal 
unbroken  period.  It  has  been  found,  however,  that  for  very 
short  intervals  the  illusion  changes  in  character,  and  such  peri- 
ods when  interrupted  at  regular  intervals  appear  to  be  longer 
than  an  equal  unbroken  time.^ 

For  the  purpose  of  investigating  this  matter  experimentally 
a  number  of  cards  were  prepared,  on  each  of  which  there  was 
marked  off  a  short  space  defined  by  limiting  lines.  The  spaces 
formed  a  series  and  were  respectively  8,9,  10,  11  and  12  mm. 
wide,  defined  at  each  extremity  by  a  pricked  line  one  centi- 
meter in  length.  The  standard  for  comparison  consisted  of  a 
space  10  mm.  wide  which  was  broken  at  regular  intervals  by 
five  lines  (Mill).  Thirty  series  (150  judgments)  were  ob- 
tained from  each  of  the  three  subjects,  B^  S  and  N.  The 
method  of  right  and  wrong  cases  was  adopted.  The  cards  to 
be  compared  were  presented  in  no  regular  order,  but  were 
shuffled  at  intervals.  A  parallel  experiment,  thirty  series  for 
each  person,  was  also  carried  out,  the  standard  in  this  ex- 
periment being  an  unbroken  space  of  10  mm.  long  (  |  |  ). 

The  results  of  the  two  experiments  are  given  in  Table  II. 
The  data  for  both  experiments  from  each  subject  are  placed  one 
below  the  other  so  that  their  comparison  may  be  more  easily 
made.  The  upper  line  of  the  table  gives  the  widths  of  the 
unbroken  spaces,  or  the  variables  which  were  compared  with 

^Meumann,  Phil.  Stud.,  IX.,  p.  264,  and  XII.,  p.  127. 


560 


ALICE  ROBERTSON. 


m 
<: 


a 

0 

•  (0 

M 

S 
S 

w 

w 

M 
M 

M 

CO 

CB 

00 

M 

M 

a 

0 

00 

0 

0 

■* 

CT\ 

M 

« 

CO 

CO 

N 

M 

d 

M 

0  . 

;(C 

a 
s 

w 

(8 

w 

P< 

■<i- 

CO 

M 

•<* 

>o 

1 

ui 

HI 

M 

0 

00 

M 

•s 

hT 

N 

>o 

00 

o\ 

t>. 

'^ 

ll 

w 

M 

M 

M 

N 

.? 

> 

0 

•>* 

M 

to 

^ 

^ 

•"rn 

M 

N 

2 

a 

W 

•0 

0 

w 

M 

10 

■* 

0 

00 

00 

00 

tH 

t^ 

«o 

„ 

0 

3 

<N 

M 

M 

M 

0 

4 

t^ 

a> 

>o 

CT\ 

t^ 

0 

■^ 

w 

3 

•d 

0   ■ 

S 

a 

a 

w 

o> 

w 

^ 

CO 

0 

00 

r^ 

0 

00 

vo 

ON 

l^ 

a\ 

CO 

W 

M 

M 

M 

j 

N 

Ht 

« 

>o 

M 

0 

« 

;-• 

0   . 

■  CO 

a 
a 

00 

W 

w 

N 

N 

10 

>o 

0 

00 

t^ 

o\ 

On 

CO 

fO 

w 

N 

cs 

W 

i-i 

1    " 

M 

VO 

M 

U      "O 

CJ       cs 

2'o'g 
5     1 

0     tn 

*«   • 

op. 

0 

0 

0 

0 

0 

0 

CO 

CO 

CO 

CO 

fO 

CO 

,  \   >.                                       1 

1 

ja 

3 
(A 

ft 

:i 

< 

0 

0 

GEOMETRIC-OPTICAL  ILLUSIONS  IN  TOUCH.  56 1 

the  two  standards.  The  letters  L,  S,  E,  E  or  S,  and  D  in  the 
second  line,  stand  respectively  for  the  judgments  longer,  shorter, 
equal,  equal  or  shorter,  and  doubtful.  The  number  of  judg- 
ments of  each  kind  is  arranged  in  two  lines  for  each  subject, 
the  upper  line  giving  the  judgment  of  comparison  with  the 
broken  standard  (Mill),  the  lower  line,  those  with  the  un- 
broken one  (I  I  ).  Thus,  taking  the  first  two  lines  which 
represent  the  judgments  given  by  the  subject  B^  we  see  that  an 
unbroken  interval  of  8  and  9  mm.,  when  compared  with  the 
standard,  is  thought  to  be  shorter  each  time.  The  comparison 
of  an  unbroken  interval  10  mm.  in  length  with  an  equal 
broken  interval  gives  28  judgments  of  shorter,  and  the  un- 
broken spaces  of  II  and  12  mm.  give  a  predominance  of  the 
judgments  of  shorter  and  equal.  Contrasting  these  results 
with  those  obtained  from  comparison  with  the  unbroken  stand- 
ard, it  will  be  seen  that  for  this  subject  there  is  ample  evidence 
for  an  overestimation  of  intervals  where  the  standard  is  10 
mm.  in  length.  In  these  sets  the  10  mm.  and  11  mm.  inter- 
vals are  the  most  instructive.  Considering  those  for  subject 
TV,  the  10  mm.  unbroken  interval  is  considered  shorter  than  an 
equal  broken  interval  17  times,  and  equal  only  4  times;  while 
the  II  mm.  interval  is  thought  to  be  longer  18  times,  and  either 
shorter  or  equal  12  times.  When  the  same  two  intervals  are 
compared  with  the  unbroken  standard,  the  judgments  of  shorter 
for  the  10  mm.  interval  diminish,  while  those  for  11  mm.  show 
almost  no  illusion. 

In  the  case  of  subject  S,  the  results  are  not  so  conclusive. 
Unlike  the  first  two  subjects,  he  knew  the  purpose  of  the  ex- 
periment and  felt,  himself,  that  this  knowledge  was  a  difficulty 
in  the  way  of  giving  a  ready  judgment.  When  the  unbroken 
standard  was  used  for  comparison,  there  is  a  slight  decrease  in 
the  judgments  of  '  shorter '  and  an  increase  of  '  doubtful '  and 
*  equal '  for  the  10  mm.  interval;  while  for  11  mm.  there  is  a 
decided  increase  of  judgments  of  'longer'  and  'equal'  with 
a  decrease  of  '  shorter.'  These  results,  when  considered  by 
themselves,  may  be  said  to  indicate  a  tendency  toward  the  over- 
estimation  of  interrupted  intervals.  Taken  in  connection  with 
those  given  by  the  two  other  subjects,  there  is  a  strong  indica- 


562  ALICE  ROBERTSON. 

tion  that  in  the  tactual  field  a  general  law  holds  true,  viz.,  that 
long  interrupted  extents  are  underestimated,  short  ones  overes- 
timated.^ 

The  underestimation  of  interrupted  extents  by  the  tactual 


Fig.  12. 

sense  is  also  shown  in  the  comparison  of  squares  which  are 
composed  of  either  horizontal  or  vertical  lines.  When  squares 
similar  to  A  and  B  (Fig.  12),  whose  sides  are  10  cm.  long,  are 
pricked  in  cardboard  and  are  felt  by  running  the  hand  as  a  whole 
over  them  from  right  to  left,  or  vice  versa,  then  an  illusion  ap- 
pears in  the  reverse  direction  from  that  perceived  by  sight.     A 


Fig.  13. 

seems  to  lengthen  so  that  it  appears  to  be  a  rectangle  whose 
horizontal  sides  are  longer  and  whose  vertical  sides  are  shorter. 
On  the  other  hand,  B  seems  to  shorten  horizontally  and  to 
lengthen  vertically.    Similarphenomenaoccurinthe  figure  which 

1  This  is  in  accord  with  the  results  of  Professor  Rieber,  to  be  published  in 
the  forthcoming  volume  of  Harvard  Studies.  Dr.  Rieber  has  very  kindly 
placed  his  results  in  outline  at  our  disposal  for  comparison. 


GEOMETRIC-OPTICAL  ILLUSIONS  IN  TOUCH. 


563 


represents  alternate  quadrants  of  interrupted  and  uninterrupted 
extents  (Fig.  13).  When  the  hand  is  passed  over  such  a  figure, 
the  open  or  uninterrupted  quadrant  seems  decidedly  the  larger. 
While  this  may  be  taken  as  added  proof  that  interrupted  extents 
are  underestimated,  yet  the  apparently  very  large  size  of  the 
open  quadrant  is  probably  due  in 
part  to  the  inclusion  by  the  hand  of 
much  of  the  surrounding  free  space. 
The  arc  through  which  the  hand 
sweeps  in  passing  over  the  open 
quadrant,  not  being  well  defined, 
seems  greater  and  may  in  reality  be 
greater  than  that  through  which  it 
passes  when  feeling  the  quadrant 
filled  with  radiating  lines.  The 
tactual  illusion  in  this  case  is  ana- 
logous to  that  which  is  found  in 
sight,  although  in  an  opposite  direc- 
tion. For,  while  in  sight  the  un- 
interrupted quadrant  seems  smaller 
than  the  filled  one,  this  is  doubtless 
partly  due  to  the  fact  that  we  com- 
pare the  arc  of  the  '  filled '  quadrant, 
i.  e.,  the  ends  of  the  radiating  lines, 
with  the  chord  of  the  arc  of  the  ad- 
joining open  quadrant.  The  optical 
illusion,  then,  is  partly  due  to  the 
leaving  out  of  some  of  the  space 
which  belongs  to  the  open  quadrant.  The  tactual  illusion,  on 
the  other  hand,  is  heightened  by  the  taking  in  of  additional 
space. 

2.  Poggendorff  Figure. — The  Poggendorff  figure  has  long 
been  a  favorite  subject  for  investigation  as  an  optical  illusion. 
Many  theories  center  about  it  and  the  closely  related  Zollner 
figure,  but  so  far  as  I  know  no  attempt  has  been  made  to  inves- 
tigate the  tactual  phenomena  connected  with  it.  A  few  tenta- 
tive experiments  gave  very  constant  and  somewhat  surprising 
results.  For  whether  the  subject  was  or  was  not  already  ac- 
quainted with  the  optical  illusion  which  appears  in  this  figure, 


/, 


Fig.  14. 


564  ALICE  ROBERTSON. 

whether  he  had  or  had  not  previously  seen  the  figure  which  was 
presented  to  him,  the  illusion  was  very  apparent,  but  in  a  reverse 
direction  from  that  which  appears  to  the  eye.  In  the  optical 
illusion  which  this  figure  presents,  the  lower  left  half  of  the 
oblique  line  appears  to  be  too  low,  and  not  directly  continuous 
with  the  upper  right  half  (Fig.  14).  In  the  tactual  illusion,  on 
the  contrary,  the  lower  left  half  of  the  oblique  seems  too  high 
to  be  considered  a  continuation  of  the  upper  right  half  of  the 
same  line.^  Moreover,  the  amount  of  displacement  in  the  tactual 
illusion  seems  to  be  much  greater  than  in  the  visual.  It  was, 
therefore,  thought  worth  while  to  conduct  a  set  of  experiments 
for  the  purpose  of  making  some  quantitative  determinations.  A 
figure  was  constructed  having  one  part  of  the  oblique  line  mov- 
able, so  that  the  amount  of  displacement  could  be  easily  meas- 
ured. The  verticals  were  placed  30  mm.  apart,  and  the  oblique 
crossed  them  at  an  angle  of  40°.  At  no  time  was  the  subject 
permitted  to  see  the  figure.  The  sheet  of  cardboard  upon  which 
it  was  constructed  was  placed  before  the  subject  so  that  his  arm 
was  2lX  right  angles  to  the  transverse  line  over  which  his  hand 
should  pass.  It  was  found  that  if  this  line  were  slowly  and 
carefully  traced  with  the  finger-tips,  the  illusion  either  did  not 
appear  or  was  very  faint.  In  all  cases  it  was  required  to  judge 
of  the  direct  continuation  of  the  two  parts  of  the  oblique  line  by 
passing  the  flat  of  the  hand  over  it,  either  alternately  up  and 
down,  or  in  one  direction  only,  as  the  subject  desired.  As  a 
matter  of  fact,  most  persons  settled  into  the  one  method  of  pass- 
ing the  hand  from  right  to  left  downward  over  the  line. 

The  experiment  was  conducted  with  four  persons,  B,  S,  D 
and  A.  From  each  of  these,  five  double  series  were  obtained. 
A  descending  series  began  with  the  transverse  lines  really  con- 
tinuous, although  in  no  case  did  they  seem  so  to  the  subject. 

'  Professor  Dresslar  proposes  an  explanation  for  an  illusion  of  displacement 
of  crossed  lines  which  he  considers  may  explain  the  optical  illusion  in  the  Pog- 
gendorff  figure,  and  which  by  implication,  at  least,  seems  to  be  intended  as  an 
explanation  of  the  tactual  illusion  in  this  figure.  In  my  own  experiments  with 
the  Poggendorflf  figure,  the  tactual  illusion  is  shown  to  be  in  an  opposite  direc- 
tion from  that  which  appears  in  sight,  and  this  fact  would  seem  not  only  to 
render  Dr.  Dresslar's  proposed  explanation  inadequate  for  the  illusion  in  touch 
but  also  to  throw  doubt  upon  that  offered  for  sight.  See  Amer.  Jour,  of  Psy., 
VI.,  p.  275. 


GEOMETRIC-OPTICAL  ILLUSIONS  IN  TOUCH. 


565 


The  movable  side  was  then  moved  downward  by  steps  of  2  or 
2.5  mm.  to  the  point  where  the  two  halves  of  the  transverse  line 
seemed  to  the  subject  to  be  continuous,  and  then  below  that 

Table  III. 

Average  Thresholds  and  Mean  Variation. 


Subject. 

Upper  Ave.  Thr. 

Lower  Ave.  Thr. 

General  Average. 

Mean  Variation. 

B 
S 
D 
A 

— 15.2  mm. 

—  27.2 

—  24.0 

—  45-0 

—  24.1 
-30.1 

—  30.1 

—  50.3 

—  19.6 

—  28.6 

—  27.1 

—  47.7 

4.6 
I8.3 
4.5 
9.0 

Aver. 

—  27.8 

—  33-6 

—  30.7 

6.6 

point  until  the  left  side  was  clearly  too  low.  An  ascending 
series  retraced  these  steps  to  zero.  Every  such  series,  of  course, 
gave  two  thresholds.  In  tabulating  the  data  a  calculated  equality 
point  was  found  of  all  the  upper  thres- 
holds for  the  upper  Hmit  of  continuity, 
or  upper  threshold.  In  a  similar  way 
the  lower  limit  of  continuity  was  found. 
Table  III.  gives  the  results  which  were 
obtained  from  each  of  the  subjects 
according  to  this  method.  In  the  table 
the  minus  sign  signifies  the  distance 
of  displacement  downward,  measured 
along  the  line  ab  in  Fig.  14. 

It  will  be  seen  that  the  mean  upper 
threshold  for  all  four  subjects  is  —  27.8 
mm.,  the  mean  lower  —33-6  mm., 
thus  giving  a  general  average  of  about 
—  31  mm.  That  is,  the  lower  left- 
hand  portion  of  the  transverse  line 
must  be  moved  downward  31  mm.  on 
an  average  before  the  two  halves  seem 
to  be  continuous.  If  we  contrast  this 
number  with  that  which  was  obtained 
by  Burmester  ^  in  his  investigation  of 
the  optical  illusion  in  the  Poggendorff  figure,  we  find  a  very 

'^  Zeitschrift  fur  Psychologic,  XII.,  p.  369. 


566 


ALICE  ROBERTSON. 


wide  difference  in  the  amount  of  displacement  which  the  two 
senses  of  sight  and  touch  reveal.  With  a  breadth  of  30  mm. 
between  the  verticals  and  an  angle  of  40°,  this  investigator 
found  an  average  of  —5.09  mm.  as  the  amount  of  displace- 
ment which  was  required  to  make  the  lines  look  continuous 
when  the  figure  was  in  a  vertical  position. 

With  some  persons  the  two  halves  of  the  oblique  line  felt  as 
if  they  were  parts  of  parallels,  but  the  lower  left-hand  portion 
seemed  to  be  at  a  higher  level  than  the  upper  right-hand  por- 
tion. It  seemed  to  be  the  unanimous  opinion  of  those  who 
experienced  this  illusion  that  the  feeling  of  '  too  high  '  was  due 
in  large  part  to  the  vertical  parallels.  These  lines,  it  was 
thought,  guided  the  hand  downward,  below  the  point  where  it 
should  cross  the  space  between  the  verticals,  and  in  order  to 
reach  the  lower  portion  of  the  transverse  line  an  actual  upward 
effort  was  necessary.  In  order  to  test  the  influence  of  the  verti- 
cals upon  the  illusion  a  second  figure  was  made,  omitting  the 
vertical  lines  altogether  (Fig.  15).  This,  like  Fig.  14,  was 
made  with  one  side  movable,  so  that  the  amount  of  displace- 
ment could  be  measured.  Five  double  series  were  obtained 
from  each  of  three  subjects,  B^  S  and  D,  and  the  upper  and 
lower  limits  noted  as  before.  The  data  are  tabulated  in  Table 
IV.,  and  some  very  interesting  results  appear.     Thus,  in  the 


Table  IV. 

Tabids  of  Average  Thresholds  and  Meax  Variation  When 
Verticals  are  Omitted. 


Subj. 

Aver.  Upper  Thr. 

Aver.  Lower  Thr. 

General  Average. 

Mean  Variation. 

B 
S 
D 

+  5-3 
—  7.2 

+    .7 

+  2.6 
-8.3 
-3-7 

+  4.0 

-7-7 
—  1.5 

3.95 
3-49 

2-5 

case  of  B  the  direction  of  illusion  changes,  and  the  lines  seem 
continuous  at  some  point  above  where  they  really  are  so.  The 
judgments  given  by  subject  D  vacillate  above  and  below  the 
zero  point,  and  if  we  take  the  average  of  the  two  thresholds 
to  be  the  point  where  the  two  lines  would  seem  continuous  to 
this  subject,  we  find  it  to  be  —  1.5  mm.  In  this  case,  then,  the 
illusion  is  practically  nothing.     With  subject  S  the  threshold 


GEOMETRIC-OPTICAL  ILLUSIONS  IN  TOUCH.  567 

always  falls  below  zero,  on  an  average  —  7.7  mm.  From  the 
data  it  seems  clear  that  in  the  absence  of  the  verticals  the 
tactual  illusion  is  very  greatly  weakened  and  almost  nil.  In 
experimenting  with  a  similar  figure,  Burmester  found  that  the 
optical  illusion  was  much  weakened  and  took  an  opposite 
direction.  This  experimenter  was  at  the  same  time  his  own 
subject,  so  that  it  is  possible  that  if  he  had  operated  with  other 
persons,  individual  differences  would  have  appeared  as  they  do 
here. 

An  attempt  was  made  to  counteract  the  influence  of  the  ver- 
ticals by  filling  in  the  space  between  the  end  of  the  oblique  lines 
with  lines  running  horizontally.  The  vertical  parallels  are  of 
course  suggested  by  the  ends  of  the  horizontals,  but  since  the 
lines  in  the  transverse  direction  are  the  more  prominent,  it  was 
thought  that  they  would  exert  the  greater  influence  and  weaken 
the  illusion,  or  perhaps  reverse  its  direction.  Several  figures 
were  made,  in  all  of  which  the  inclination  of  the  oblique  line 
remained  constant,  30°,  but  in  which  both  the  lengths  of  the 
horizontal  lines  and  their  distance  apart  varied.  The  results  of 
experimentation  indicated  a  decided  weakening  of  the  illusion, 
but  in  no  case  was  reversal  obtained. 

In  whatever  position  the  Poggendorff  figure  in  its  normal 
form  was  laid,  illusion  was  apparent.  The  amount  of  pressure 
exerted,  and  the  rapidity  of  movement,  seem  to  have  an  effect 
upon  the  amount  of  apparent  displacement.  Thus,  in  the  case 
of  a  figure  in  which  the  oblique  lines  were  fixed,  it  was  found 
that,  with  hard  pressure  and  rapid  movement,  the  lower  left- 
hand  line  seemed  too  high  ;  whereas,  with  the  same  pressure 
approximately,  and  slow  movement,  the  two  halves  of  the 
oblique  line  seemed  to  be  continuous. 

Various  theories  suggest  themselves  as  a  partial  explanation  of 
the  tactual  illusion  which  is  exhibited  by  the  Poggendorff  figure. 
That  the  verticals  in  some  way  influence  the  amount  and  direc- 
tion of  illusion  in  both  sight  and  touch  is  obvious  enough.  To 
some  persons  they  seemed  to  exert  a  mechanical  influence  in 
actually  leading  the  hand  astray,  so  that  in  passing  downward 
from  the  upper  right-hand  oblique  to  the  lower  left,  an  upward 
effort  is  necessary  in  order  to  find  the  lower  part  of  the  line, 


56S  ALICE  ROBERTSON. 

leading  the  subject  to  consider  that  that  portion  of  the  line  is  on 
a  higher  level.  An  attempt  was  made  to  get  tracings  of  the 
path  which  the  hand  described  in  passing  from  one  portion  of 
the  oblique  to  the  other.  This  was  done  by  placing  strips  of 
smoked  paper  in  the  path  of  a  wire  which  was  attached  to  the 
hand.  Thus,  in  one  instance  when  the  lower  oblique  was  moved 
downward  10  mm.,  in  passing  the  hand  from  above  downward 
the  two  halves  seemed  continuous,  while  in  passing  from  below 
upward  the  lower  left  part  of  the  oblique  seemed  too  high  ; 
in  these  two  instances,  however,  no  difference  can  be  detected 
in  the  two  tracings.  That  part  of  the  curve  which  represents 
the  path  of  the  hand  between  the  verticals  is  almost  a  straight 
line  in  both  cases,  and  each  is  the  normal  and  regular  continua- 
tion of  the  first  part  of  the  tracing.  In  another  instance,  the 
two  obliques  were  separated  by  a  vertical  distance  of  18  mm. 
To  the  subject  the  lines  seemed  continuous  with  both  the  upward 
and  downward  movement,  and  the  smoked  paper  tracings  were 
two  perfectly  even  and  smooth,  almost  parallel  lines.  In  a  third 
instance  the  obliques  were  separated  by  a  vertical  distance  of 
23  mm.  At  this  point  they  seemed  continuous  to  the  subject, 
while  the  tracing  shows  many  irregularities.  These,  however, 
occur,  not  only  in  the  space  between  the  verticals,  but  through- 
out the  lines,  and  may  be  ascribed  to  natural  tremors  of  the  hand. 
There  is  no  evidence  that  there  is  an  actual  upward  movement 
of  the  hand  corresponding  to  the  effort  which  some  subjects  be- 
lieved they  felt. 

Data  obtained  from  figures  similar  to  those  used  in  these  ex- 
periments have  afforded  a  basis  for  opposing  theories  of  space 
perception.  The  perspective  theory  of  Thiery  has  already 
been  mentioned.  He  sees  in  the  Poggendorff  figure  also  a 
definite  perspective  effect  which  is  the  cause  of  the  apparent 
shifting  of  the  two  halves  of  the  oblique  line.  Professor 
Wundt^  considers  that  the  cause  of  the  optical  illusion  in  this 
figure  is  the  overestimation  of  the  acute  angles.  The  perspec- 
tive effect,  he  maintains,  appears  only  when  one  fixates  a  point 
monocularly,  at  which  time  the   displacement  of  the   oblique 

^ '  Die  geometrisch-optischeii  Tiiuschungen,'  Abhandl.  d.  konigl.  sacks. 
Gesellsch.  d.  JVissensc/i.,  XLII. 


GEOMETRIC-OPTICAL  ILLUSIONS  IN  TOUCH.  569 

lines  disappears  entirely.  The  '  asthetisch-mechanische '  theory 
of  Lipps/  offered  first  as  an  explanation  of  spatial  form,  has 
later  been  applied  to  geometrical  optical  illusions.  Among 
other  figures,  this  writer  discusses  the  Poggendorff  figure.  He 
applies  to  it  his  theory  of  the  interaction  of  opposing  forces,  and 
considers  that  it  suggests  the  action  of  the  two  forces  of  gravity 
and  vertical  extension.  The  oblique  line  represents  a  force  ap- 
proaching, but  not  attaining,  verticality.  In  the  struggle  this 
force  is  regarded  as  the  primary  activity,  and  as  primary  ac- 
tivity is  overestimated. 

We  have,  then,  at  least  three  explanations  of  the  phenomena 
of  the  Poggendorff  figure.  It  is  here  shown  how  the  same 
figure  may  give  very  different  sensations  to  the  skin.  How  are 
the  facts  to  be  reconciled?  If  the  optical  phenomena  of  this 
figure  are  due  to  the  overestimation  of  the  bending  of  the  ob- 
liques away  from  the  vertical,  according  to  Lipps,  or  if  they  are 
due  to  an  overestimation  of  the  small  angles,  according  to 
Wundt,  why  should  not  these  causes  operate  in  the  field  of 
touch,  and,  if  they  do,  why  should  opposite  effects  be  produced 
upon  the  tactual  sense?  Likewise,  no  explanation  for  the  op- 
tical illusion  in  the  ring  segments  satisfies  the  touch  phenomena 
in  the  same  figures.  Here  again,  perspective  effects  and  the 
overestimation  of  small  angles  are  offered  in  explanation.  But 
the  illusion  persists  in  touch,  when  none  is  apparent  to  sight, 
and  when  all  perspective  and  almost  all  angle  effect  is  lost  com- 
pletely. The  data  which  are  afforded  by  experiments  in  the 
tactual  field  suggest  a  revision  of  the  theories  so  far  offered  for 
spatial  illusions  in  general.  These  theories  are  in  the  main 
founded  upon  optical  phenomena.  From  what  appears  in  the 
tactual  field  it  is  reasonable  to  suppose  that  further  study  may 
assist  in  elucidating  this  very  complex  and  difficult  problem. 

' '  Raumasthetik  und  geometrisch-optische  Tauschuugen,'  Schriften  de? 
Gesell.fiirpsy.  Forschung,  Vol.  II.,  p.  295. 


Ilfllrcfsity  of  Cailfflfoia 

PsjKiiioioglcal  Laborxtory, 


REPRINTED  FROM 

Vol.  XII.  No.  1.  January,  1905. 

THE 

Psychological   Review 

EDITED  BY 
J.  MARK  BALDWIN  HOWARD  C.  WARREN 

Johns  Hopkins  University  ^^°  Princeton  University 

CHARLES  IL  JUDD,  Yale  University  {Editor  of  the  Monograph  Series). 

WITH  THE  CO-OPERATION  FOR  THIS  SECTION  OF 

A.  C.  ARMSTRONG,  Wesleyan  University  ;  ALFRED  BINET,  Ecole  des  Hautes- 
^tudes,  Paris  ;  W.  L.  BRYAN,  Indiana  University  ;  WILLIAM  CALDWELL,  Mc- 
GiLL  University;  MARY  W.  CALKINS,  Wellesley  College;  JOHN  DEWEY, 
Columbia  University  ;  J.  R.  ANGELL,  University  op  Chicago;  C.  LADD  FRANKLIN, 
Baltimore;  H.  N.  GARDINER,  Smith  College;  G.  H.  HOWISON,  University  of 
California)  P,  JANET,  College  de  France ;  JOSEPH  JASTROW,  University  of  Wis- 
consin; ADOLF  MEYER,  N.  Y.  Pathol.  Institute;  C.  LLOYD  MORGAN,  University 
College,  Bristol;  HUGO  MONSTERBERG,  Harvard  University;  E.  A.  PACE, 
Catholic  University,  Washington  ;  G.  T.  W.  PATRICK,  University  of  Iowa;  CARL 
STUMFF,  University,  Bkulin;  R.  W.  WENLEY,  University  of  Michigan. 


FROM  THE  UNIVERSITY  OF  CALIFORNIA  PSYCHO- 
LOGICAL LABORATORY 

communicated  by  g.  m.  stratton 

The  Effect  of  "Verbal  Suggestion    upon  the  Estimation 
OF  Linear  Magnitudes 

By  JOSEPH  E.   J5RAND 

Late  Assistant  in  the  California  l^syclioloiical  Laborat.iry. 


THE  MACMILLAN  COMPANY, 

41    NORTH   QUEEN   ST.,    LANCASTER,    PA. 
66  FIFTH   AVENUE,  NEW  YORK 

Agent:  G.  E.  STECHERT,  London  (2  Star  Yard,  Carey  St.,  W.  C, 
Leipzig  (Hospital  St.,  10);   PariS  (76rus  de  Reunea). 


Ps^iihoiO'f'nsi  !s^'' 


42  JOSEPH  E.  BRAND. 

the  lower  one  being  2.2  cm.  in  width,  and  the  upper  one  i  cm. 
in  width,  having  behind  them  backgrounds  of  the  same  black- 
ness as  the  screens.  Through  the  lower  slot  and  against  this 
background  were  exposed  the  printed  slips  bearing  the  mottoes, 
resting  on  a  wooden  ledge  fastened  to  the  back  of  the  screen 
just  below  the  edge  of  the  slot.  On  a  similar  ledge  behind  the 
upper  slot  were  exposed  two  white  pegs  .8  cm.  in  diameter  and 
long  enough  to  have  their  ends  hidden  by  the  screen.  These 
pegs  could  be  moved  along  the  ledge,  and  hence  adjusted  for 
various  intervals  between  them.  On  the  near  side  of  the  nearer 
screen  and  just  below  the  top,  was  a  ledge  on  which  the  subject 
moved  little  pegs  similar  to  those  just  described,  and  thus  repro- 
duced his  estimation  of  the  standard  interval. 

Over  the  front  of  the  farther  screen  was  made  to  slide  a 
movable  screen  having  a  single  horizontal  slot  through  which 
either  of  the  two  slots  in  the  stationary  screen  could  be  exposed, 
but  not  both  together.  Thus  the  subject  saw  either  the  motto 
in  the  lower  slot,  or  else  the  standard  distance  marked  off  by 
the  two  white  pegs  appearing  as  rectangles  i  x  .8  cm.  in  the 
upper  slot,  or  else  both  slots  were  altogether  hidden.  The  dis- 
tance from  the  subject's  eye  to  the  nearer  screen  was  40  cm., 
and  from  the  nearer  screen  to  the  farther  was  80  cm. 

The  mode  of  operating  the  apparatus  was  sufficiently  sim- 
ple. The  proper  motto  being  in  the  lower  slot,  and  the  pegs 
having  been  properly  spaced  in  the  upper,  and  both  slots  being 
hidden  by  the  movable  screen,  the  operator,  after  due  warning 
to  the  subject,  raised  the  screen  one  notch  and  exposed  the 
motto  for  two  seconds  ;  then  raised  it  a  second  notch  and  exposed 
the  standard  interval  for  two  seconds  ;  then  dropped  it  one  notch 
and  left  the  motto  again  exposed.  The  subject  immediately  so 
placed  his  pegs  on  the  ledge  as  to  mark  off  his  estimate  of  the 
space  interval,  and  the  operator  recorded  the  length  so  marked, 
reading  it  from  a  scale  hidden  from  the  subject's  vision  by  a 
narrow  strip  of  black  paper  projecting  above  the  ledge. 

I.    First  Set  of  Experiments. 
In  this  first  work  only  two  subjects  were  engaged  and  a  variety 
of  suggestion  mottoes  were   used,  viz.,  ^  Make  short  enough^ 


EFFECT  OF  VERBAL    SUGGESTION.  43 

*  Make  long  enough,,'  '  Don't  make  too  long,'  '  Don't  make  too 
shorty'  '  Make  shorty'  '  Make  long,'  a  nonsense  motto  '  Zwffjvic 
bgzx  asye,'  and  a  meaningless  sentence  '  Ltfe  is  real  where.'' 
These  mottoes  were  printed  in  black  capitals  1.2  cm.  high  on 
white  cardboard. 

In  groups  A,  B  and  C  four  standard  lengths  for  estimatio 
were  used,  16,  22,  28  and  34  cm.  In  group  D  standards 
of  24,  26,  30  and  32  cm.  for  subject  C.  and  12,  14,  18  and  20 
cm.  for  subject  Y.  Long  standards  were  used  for  subject  C.  in 
this  group  because  from  examination  of  results  in  the  preceding 
groups  it  seemed  that  the  long  standards  would  give  more  defi- 
nite results  ;  and  since  standards  for  this  subject  were  changed, 
it  was  thought  advisable  to  change  standards  for  the  other  sub- 
ject also.  Thus  any  possible  difficulty  from  too  long  use  of  the 
same  standards  was  obviated.  The  four  standards  employed  in 
any  group  were  given  in  succession  with  each  motto,  in  an  order 
determined  by  lot,  the  order  of  succession  of  the  mottoes  being 
changed  for  each  day.  A  '  nonsense  motto  '  was  used  in  order 
that  the  tests  without  suggestion  might  be  under  conditions  as 
like  as  possible  to  the  others,  except  for  the  suggestion  itself. 

Tables  I.  and  II.  give  in  detail  the  results  of  this  investiga- 
tion. Instead  of  finding  the  average  lengths  reproduced  with 
different  mottoes  it  was  deemed  simpler  to  interpret  the  data  by 
aggregation.  The  number  tabulated  under  a  given  motto  for  a 
given  day  is  therefore  the  sum  of  all  the  judgments  taken  that 
day  for  that  motto.  As  remarked  above,  the  series  in  both  tables 
are  arranged  in  four  groups,  which  differ  amongst  themselves 
in  regard  to  the  mottoes  and  standards  used,  and  also  in  that  a 
month's  interval  elapsed  between  the  work  of  group  C  and  that 
of  group  D.  For  convenience  in  examining  the  tables,  totals 
are  given  under  each  group  for  such  columns  as  it  is  desirable 
to  compare.  As  all  the  mottoes  are  not  used  on  all  the  davs, 
only  such  days  are  included  in  forming  the  totals  as  make  the 
totals  in  the  same  horizontal  line  properly  comparable. 

An  examination  of  these  tables  leads  to  some  interesting 
conclusions.  First,  we  find  by  comparison  of  daily  totals  and 
general  totals,  that  the  suggestion  produces  a  definite,  though 
slight,  effect.     The  results  for  '  Make  short  enough '  are  in  both 


44 


JOSEPH  E.  BRAND. 


Table   I. 
Based  on  650  Judgments  ;  Subject,  Miss  C. 


I 

2 

3       14               5               6 

7 

8  Vi 

9 

10 

XI 

6. 

s 

2 
0 

"0 
>. 

cd 

Q 

of 

S  3 

a  6 

K  - 

tn  u 

Ai  S. 

H 

V  3 
M  0 

5  bo 

It 

i2  a 

V 

n 

Group  A 

( Eight  different 
standards,  11-30 
cm.   long,  were 
used      in      this 
group) 

I 

2 

3 
4 
5 
6 

9 

8 
10 
10 
10 
15 

189 

167 
202 
202 
202 
320 

199 

179 

221.5 

218 

343-6 

227 

224.5 
220 

212.7 

225 

214 
221.5 

341.5 

180.7 

223.5 

220 

216 

224 
223 

221 

342.9 

Sumof  days3,4,5 

3.  4,  5,  6... 

3.  4,  6... 

30 
45 
35 

606 
926 
724 

783.1 



671-5 

660.5 
1,002 
780.5 

659-5 

668 
1,010.9 
789.9 

Group  B 
(Standards,    16, 
22,  28,  34  cm.).. 

2 
3 
4 

II 
16 

24 
24 

248 
322 

5b8 
660 

259.2 
302.5 
584 
650.7 

258.3 
305.2 
597-6 
680.3 

Sum 

75 

1,818 

1,796.4 

1,841.4 

Group  C 
(Standards.    16, 
22,  28,  34  cm.)... 

I 
2 
3 

8 
9 
9 

200 
210 
204 

216.6 
196.2 
200.5 

205 

202.1 

198.2 

210.2 
196-3 
194.3 

211.7 
205.4 
202.1 

Sum 

26 

614 

613-3 

605.3 

600.8 

619.2 

Group  D 
(Standards,    24, 
26,  30,  32  cm.)... 

I 

2 

3 
4 

6 
10 

7 
6 

170 
276 
206 
162 

279.1 

209 

165.6 

279.1 

2II.6 

157-3 

183.2 
284.6 
221.7 
165.2 

175-3 
280.5 
213.6 
156.2 

172 

279 
203.3 

164.5 

185.5 
279.6 
212.5 
170 

S.  of  days  i,  2,3,4 
2,  3,  4... 

29 
23 

814 
644 

653-7 

648 

854-7 
671-5 

825.6 
650.3 

818.8 
646.8 

847-6 
662.1 

Total,  (r&Z>( ex- 
cept day  i) 

Total,  A  (except 
daysi,2)C&Z? 

Total,  i9&Z> 

49 

100 
104 

1,258 

2,354 
2,632 

1,267 

1,253.3 

1,272.3 
2,457.5 

— 

1,269.5 
2,455-7 

2,615.2  2,689 

cases  greater  than  those  for  '  Make  long  enough ' ;  the  results 
for  '  Make  long '  are  greater  than  those  for  '  Make  short '  for 
subject  C,  and  also  greater  for  subject  Y.  in  group  Z),  although 
less  in  group  B  for  this  subject.  Similarly,  results  for  '  Don't 
make  too  long '  are  pretty  uniformly  greater  than  those  for  '  Don't 
make  too  short'  for  subject  Y.,  and  also  for  subject  C.  in  group 
Z),  but  not  for  this  observer  in  groups  A  and  C. 


EFFECT  OF  VERBAL    SUGGESTION. 


45 


Table   1 1. 
Based  on  598  Judgments  ;  Subject,  Mr.  Y. 


I 

2 

3        1        4 

S 

6 

7 

8 

9 

10 

II 

0. 

I 

"o 
0 

3  ed    - 

Standard 
(Sum). 

Nonsense 
Motto. 

"3 

V- 
10  u 

•'"  I) 
MA 

1^ 

-•a 

1^ 

ba 

% 

V 

0  2 

-  tn 

Group  A 

(Eight  standards 
11-30  cm.  long). 

I 

2 

3 
4 

9 
10 
10 
15 

189 
202 
202 
320 

176 
188 
186.5 
297.6 

197 
191 
289 

176.5 
188 
190 
293.8 

179.7 
192-5 
194-5 

190.5! 
186.5 
289.2 

Sumofdavs,  2,3,  4 
2,  3... 

35 
20 

724 

404 

672.1 

374-5 

388 

671.81      — 

378     1387 

666.2: 

377    ' 

Group  B 
(Standards  16,  22, 
28.  ^4) 

I 
2 
3 
4 

21 
22 

19 
20 

534 
538 
514 

524 

503-3 
499-9 
499.8 
487.2 

487.8 
491 
500.9 
488.5 

Sum 

82 

2,110 

1.QQ0.2 

1,968.2 

1 

1         -^  " 

Group  C 
(Standards  16,  22, 
28,  ^4) 

I 
2 

3 

II 
II 
9 

320 
278 
198 

283.9 
252.5 
176.5 

276.8 
248.8 
178. 1 

285.1 
258-5 

I75-I 

287.8 
255-6 
172.2 

Sum 

31 

7q6 

712. Q 

703-7 

718.7I 

715-6 

i 

Group  D 
(Standards  12, 14, 
18    20") 

I 

2 
3 

6 
6 
6 

98    94.7 

90      86.6 
102      94.9 

91.7 
86.3 

94-3 

i 
92    1 

89.8 
94-31 

94-3 
88.1 
91 

92.2 
85.6 

Ql.d 

92.8 
i       92-4 

Sum 

18 

290    276.2 

272.3 

1 

276.1 

273.4'    269.2'    280.2 

Total,  Cand  D 

Total,   A   (except 

day  I)  CD 

Total,  B  and  D 

1 

49 

84 
100 

1,086 

1,810 
2,400 

1  989.1 

976 

994.8 
1,666.6 

989    j      -      ;      - 

1,655-2       —           — 

2,259.42,248.4 

Since  group  B  followed  group  A  and  group  C  followed 
group  B  without  gap,  but  a  month  elapsed  between  groups  C 
and  Z?,  and  since  the  difference  in  the  presumable  effects  of 
the  same  mottoes  occurs  only  between  group  D  and  the  other 
groups,  we  must  conclude  that  the  uniformity  is  too  great  to 
admit  of  an  explanation  except  by  potency  of  the  suggestion 
from  the  mottoes. 

Second,  this  suggestion-effect  varies  both  according  to  the 
individual  to  whom  the  suggestion  is  made,  and  also  according 
to  circumstances.  The  disagreements  just  referred  to  as  existing 
between  group  D  and  the  preceding  groups  is  evidence  upon  the 


46 


JOSEPH  E.  BRAND. 


latter  of  these  points.  The  data  within  these  groups  are  reason- 
ably self-consistent,  showing  that  on  almost  every  separate  day 
the  same  effect  was  produced,  but  that  during  the  month's  inter- 
val the  subject  had  gotten  over  into  a  condition  such  that  the 
difference  between  the  effects  produced  upon  him  by  two  oppos- 
ing formal  suggestions  was  of  opposite  sign  to  what  it  was 
earlier. 

Third,  the  mere  words  '  long '  and  '  short,'  regardless  of 
their  content,  seem  to  affect  the  estimation  under  certain  cir- 
cumstances. This  is  illustrated  by  Table  III.,  which  gives  the 
sums  for  the  mottoes  containing  the  word  '  short '  and  the  sums 
for  those  containing  the  word  '  long '  from  group  D  of  both 
tables. 

Table  III. 


Subject. 

No.  of  Judgments. 

Standard. 

Mottoes  Containing  the  Word 

"Long.  • 

"Short." 

c. 

Y. 

58 
36 

1628 

580 

1702.3 
556.3 

1644.4 
542.6 

From  this  table  it  will  be  seen  that  the  total  for  mottoes  con- 
taining the  word  '  short '  is  less  in  both  cases  than  that  for 
mottoes  containing  the  word  '  long.'  Similar  totals  from  group 
A  give  exactly  opposite  results  for  Table  I.,  and  neutral  results 
for  Table  II.  (/.  e.,  in  the  latter  case  the  totals  are  about  equal). 

Now  these  results,  taken  as  they  are  merely  from  the  group 
totals,  may  either  be  the  result  of  chance,  or  they  may  be  due 
to  the  existence  of  a  different  attitude  towards  positive  and  nega- 
tive suggestions,  causing  the  subject  at  any  given  time  to  incline 
to  act  in  accordance  with  one  and  in  opposition  to  the  other ;  or 
they  may  be  due  to  a  tendency  to  be  influenced  by  the  mere 
words  '  short '  and  '  long,'  as  said  above.  The  likelihood  of  this 
latter  explanation  led  to  the  group  of  experiments  which  follow 
under  section  2. 

Fourth,  a  motto  which  has  interest  for  a  subject  seems  to 
give  greater  lengths  in  the  reproduction  than  an  uninteresting 
one.  The  nonsense  mottoes  in  group  A  (except  for  a  single 
day  for  subject  Y.)  give  smaller  totals  than  do  the  other  mottoes, 
which  in  this  part  of  the  experiment  were  not  yet  so  familiar  as 


EFFECT  OF  VERBAL   SUGGESTION.  47 

to  lack  interest ;  while  in  groups  C  and  D  the  motto  '  Life  is 
real  where,'  which  the  subjects  declared  was  much  more  empty 
and  uninteresting  than  the  '  nonsense  '  motto,  and  hence  should 
be  taken  as  the  criterion  in  these  groups,  gives  smaller  totals 
than  the  averages  for  the  suggestion  mottoes,  as  show  in  Table 
IV. 

Table  IV. 


Mottoes  with  content. 

(Average  of  columns 

Mottoes  without  content, 

Subject. 

\^  and  9  of  groups  C 

(Total  of  column  5  of 

D,  omitting  row 

same  days.) 

I  of  A  Table  I.) 

C.  (Table  I.) 

1270.8 

1253-3 

Y.  (Table  II.) 

991.9 

976.0 

The  indication  of  this  comparison  is  of  course  very  unsatis- 
factory, but  seems  at  least  to  warrant  a  special  investigation  on 
this  point. 

2.  Second  Set  of  Experiments. 

The  apparent  effect  of  the  mere  words  '  long  '  and  '  short '  in 
the  first  set  of  experiments  led  to  the  second  set,  in  which  the 
mottoes  used  were  only  three  in  number,  viz.  :  '  long,'  '  short,' 
and  '  XXXX.'  The  apparatus  differed  from  that  described 
above  only  in  the  substitution,  for  the  pegs,  of  white  paper 
squares  on  a  black  screen,  one  square  of  the  pair  being  on  a 
strip  of  black  paper  running  in  grooves  behind  a  slot  in  the 
screen,  so  that  the  adjustments,  i.  e.,  the  various  distances  of 
separation  of  the  squares,  were  obtained  by  simply  sliding  the 
strip  along.  Three  standard  distances  were  used,  viz.  :  17,  18 
and  19  cm.,  being  given  in  such  order  that  each  was  preceded 
by  each  of  the  others  about  an  equal  number  of  times,  and  each 
of  the  three  used  an  equal  number  of  times  on  the  same  day. 
Each  of  the  mottoes  was  given  an  equal  number  of  times  with 
each  of  the  standards,  in  order  determined  by  lot.  The  letters 
of  the  mottoes  were  so  spaced  as  to  cover  the  same  extent  in 
every  case  and  so  exclude  the  possibility  of  a  difference  due 
to  mere  space  contrast  or  assimilation. 

Four  subjects  were  employed,  and  the  results  were  not  very 
uniform,  two  of  the  subjects  showing  no  decided  tendency 
towards  anything  resembling  a  constant  effect,  while  the  other 


48 


JOSEPH  E.  BRAND. 


two  subjects,  showed  a  clear  general  constancy  of  considerable 
difference  throughout.  The  results  for  these  two  are  given  in 
Tables  V.  and  VI. 

Table  V. 
Subject  K. 


Date. 

Standard. 

Times 
Used. 

Sum  for 
Standard. 

Sum  for 
"I<ong." 

Sum  for 
"Short." 

Sum  for 
"XXXX." 

Sept.  i8. 

17 
18 

19 

3 
3 
3 

51 
54 
57 

47.8 
53.6 

54-8 

48.4 
52.4 
56.2 

48.3 
53-9 
58.0 

162 

156.2 

157.0 

160.2 

Sept.  24. 

17 
iS 

19 

5 
5 
5 

85 
90 

95 

79-9 

84.4 
93.5 

79.2 
84-3 
95-5 

81.5 
85.1 
94-3 

270 

257.8 

259.0 

260.9 

Sept.  25. 

17 
18 

19 

6 
6 
6 

102 
108 
114 

94-6 
104.9 
107.5 

98.6 
104.4 
113.6 

98.3 
103.0 
III. 7 

324 

307.0 

316.6 

3130 

Sept.  26. 

17 
18 

19 

6 
6 
6 

102 
108 
114 

92.7 
106.6 
1 10.4 

96.8 
107.2 
112.1 

95-1 
105.0 
112. 9 

324 

309.7 

316.1 

313.0 

Oct.     2. 

17 
18 

19 

6 
6 
6 

102 
108 
114 

94.1 
101.8 
III. 4 

95.5 
104.5 
114.8 

92.7 
103.8 
II3-7 

324 

307.3 

314.8 

310.2 

Oct.     4. 

17 
18 

19 

4 
4 
4 

68 
72 
76 

58.1 
67.2 

72.7 

62.3 
65.7 
73-4 

60.6 
68.6 
73.2 

216 

198.0 

201.4 

202.4 

Grand  Total. 

90 

1620 

1536.0 

1564.9 

1559.7 

By  examining  Tables  V.  and  VI.  it  will  be  seen  that  for 
Subject  K.  the  figures  for  the  motto  '  short '  are  with  two 
exceptions  greater  than  the  figures  for  the  motto  '  long,'  and 
for  subject  M.  the  reverse  is  true,  again  with  two  exceptions. 
In  the  daily  totals,  however,  there  are  no  exceptions.  In  spite 
of  the  fact  that  the  other  two  subjects  gave  neutral  results,  the 
hypothesis  that  the  words  '  long '  and  «  short '  of  themselves  are 
capable  of  influencing  the  estimation  of  distances  seems  well 


EFFECT  OF  VERBAL    SUGGESTION. 

Table  VI. 

Subject  M. 


49 


Date.         Standard. 

Times 
Used. 

Sum  for 
Standard. 

Sum  for 
"Long." 

Sum  for 
"Short." 

Sum  for 
"XXXX." 

Sept.    5- 

iS 
19 

6 
6 

108 
114 

108.3 
123.2 

103.2 
II7.0 

108.8 
I16.8 

222 

231-5 

220.2 

225.6 

Sept.    6. 

17 
18 

7 
5 

119 
90 

II8.2 
92.8 

113.0 
91.3 

I18.5 

86.1 

209 

211. 0 

204.3 

204.6 

Sept.  II. 

18 
19 

8 
6 

144 
114 

144.6 
I16.O 

140.5 
II7.8 

141.7 
112. 1 

258 

260.6 

258.3 

253.8 

Sept.  13. 

17 
18 

8 
8 

136 

144 

139.8 
148.3 

134.6 
145-5 

137.8 
146.6 

280 

288.1 

280.1 

284.4 

Oct.     7. 

17 
19 

7 
7 

119 
133 

II7.3 
130.2 

116.0 
134.3 

119.0 

134.7 

252 

247-5 

250.3 

253.7 

Oct.    II. 

17 
19 

7 
7 

119 

133 

121. 0 
136.7 

115.0 
132.5 

117.4 
138.0 

252 

257-7 

247.5 

2554 

Oct.    14. 

17 
18 

19 

I 
3 
4 

17 

54 
76 

17.1 

50.3 
76.2 

16.0 
48.9 
72.7 

17.0 
52.9 
75.1 

M7 

143.6 

137.6 

145.0 

Grand  Total. 

90 

1620 

1640.0 

1598.3 

1622.5 

grounded,  for  in  view  of  the  discussion  of  the  first  group  of 
experiments  we  might  expect  that  the  suggestion  effect  would 
be  contrary  in  certain  different  subjects,  and  lacking  in  others. 
Thus  the  influence  of  purely  formal  and  arbitrary  suggestion 
seems  even  more  clearly  evidenced  by  this  second  group  of 
experiments  than  by  the  first. 


Onlifcrsitf  of  California 

Psyotiological  laboratoni. 


?^ 


REPRINTED  FROM 

Vol.  XII.  No.  1.  January,  1905. 

THE 

Psychological    Review 

EDITED  BY 
J.  MARK  BALDWIN  HOWARD  C.  WARREN 

Johns  Hopkins  University  ^^^  Princeton  University 

CHARLES  H.  JUDD,  Yale  University  [Editor  of  the  Monograph  Series). 

WITH  THE  CO-OPERATION  FOR  THIS  SECTION  OF 

A.  C.  ARMSTRONG,  Wesleyan  University  ;  ALFRED  BINET,  £cole  des  Hautes- 
6tudes,  Paris  ;  W.  L.  BRYAN,  Indiana  University  ;  WILLIAM  CALDWELL,  Mc- 
GiLL  University;  MARY  W.  CALKINS,  Wellesley  College;  JOHN  DEWEY, 
Columbia  University  ;  J.  R.  ANGELL,  University  op  Chicago  ;  C.  LADD  FRANKLIN, 
Baltimore;  H.  N.  GARDINER,  Smith  College;  G.  H.  HOWISON,  University  of 
California  ;  P.  JANET,  College  de  France  ;  JOSEPH  JASTROW,  University  of  Wis- 
consin; ADOLF  MEYER,  N.  Y.  Pathol.  Institute;  C.  LLOYD  MORGAN,  University 
College,  Bristol;  HUGO  Mt^NSTERBERG,  Harvard  University;  E.  A.  PACE, 
Catholic  University,  Washington;  G.  T.  W.  PATRICK,  University  of  Iowa;  CARL 
STUMPF,  University,  Berlin;  R.  W.  WENLEY,  University  of  Michigan. 


FROM  THE  UNIVERSITY  OF  CALIFORNIA  PSYCHO- 
LOGICAL LABORATORY 

communicated  by  g.  m.  stratton 

Experiments  on  the  Unreflective  Ideas  of  Men 
AND  Women 

By  GENEVIEVE  SAVAGE  MANCHESTER 


THE  MACMILLAN  COMPANY. 

41   NORTH  QUEEN  ST.,    LANCASTER,    PA. 
66  FIFTH   AVENUE,  NEW  YORK 

Agbnt:  G.  E.  STECHERT,  London  (2  Star  Yard,  Carey  St.,  W.  C); 
Lbipzig  (Hospital  St.,  10):   Paris  (76  rue  de  Rennes). 


lirkrsitj  si  Caiifornii! 


[Reprinted  from  The  Psychological  Review,  Vol.  XII.,  No.  i,  Jan.,  1905.] 


VIII.    Experiments  on  the  Unreflective  Ideas  of  Men 

AND  Women. 

BY  GENEVIEVE  SAVAGE  MANCHESTER. 

In  1891,  Professor  Jastrow  made  a  study  ^  of  the  mental  dif- 
ferences of  men  and  women,  using  as  material,  lists  of  one 
hundred  words  each,  written  by  men  and  women  students  in 
his  classes.  These  lists  were  written  as  rapidly  as  possible  in 
order  that  they  should  be  natural  and  unreflective.  From  a 
comparison  of  twenty-five  men's  lists,  with  an  equal  number  of 
the  women's  lists,  he  concluded  that  the  feminine  traits  of  mind 
revealed  by  the  study  are  :  '  An  attention  to  immediate  sur- 
roundings, to  the  finished  product,  to  the  ornamental,  the  indi- 
vidual, and  the  concrete,  while  the  masculine  preference  is  for 
the  more  remote,  the  constructive,  the  useful,  the  general,  and 
the  abstract.'  A  few  years  later,  a  similar  experiment  was 
made  at  Wellesley  College.  Miss  Nevers,^  who  made  the 
study,  found  that  her  results  were  strikingly  different  from 
those  obtained  by  Dr.  Jastrow.  Later,  however,  it  was  discov- 
ered that  for  the  most  part,  this  difference  in  results  was  due  to 
a  deviation  in  method,  the  instruction  to  write  the  lists  as  rap- 
idly as  possible,  having  been  omitted  by  Miss  Nevers.  A  repe- 
tition of  the  experiment  conforming  closely  to  Professor  Jas- 
trow's  procedure  produced  results  which  supported  some  of  his 
conclusions,  but  not  all.^ 

1  New  Review,  Vol.,  V,  1891,  pp.  559  to  569. 

2  Psychological  Rbjvibw,  1895,  pp.  361  to  367. 

^  Other  experiments  on  the  mental  diflferences  of  men  and  women  have 
been  carried  on,  though  not  along  the  lines  suggested  by  Professor  Jastrow. 
Helen  Bradford  Thompson,  in  a  study  of  the  mental  differences  of  men  and 
women  came  to  the  following  conclusions  {Psychological  Norms  in  Men  and 
Women,  Univ.  Chic.  Press,  1903,  page  171)  :  "  Women  are  decidedly  superior 
to  men  in  memory,  and  possibly  more  rapid  in  associative  thinking.  Men  are 
probably  superior  in  ingenuity.  In  general  information  and  intellectual  inter- 
ests there  is  no  difference  characteristic  of  sex."  For  other  references  and 
results  V.  Havelock  Ellis'  Man  and  Woman  (Contemp.  Science  Series). 

50 


Onlverslty  of  California 

Psyiiliological  Laboratoi). 


51  GENEVIEVE   SAVAGE  MANCHESTER. 

Preliminary  to  a  further  study  of  the  mental  differences  of  the 
sexes,  I  have  repeated  Dr.  Jastrow's  experiment  at  the  Univer- 
sity of  California.  To  get  the  required  lists,  all  the  men  and 
women  in  several  classes  in  general  psychology  were  given 
blank  sheets  of  paper  on  which  were  spaces  for  lOO  words,  the 
writer's  name,  sex  and  the  time  required  to  write  the  list.  The 
only  instructions  given  were  to  write  at  top  speed  and  to  avoid 
writing  words  in  sentences.  From  the  large  number  of  papers 
received,  three  sets  were  selected,  each  set  containing  twenty-- 
five  men's  lists  and  twenty-five  women's.  In  selecting  the  lists, 
the  only  requirements  were  that  the  lists  should  seem  natural 
and  unreflective  and  that  the  same  word  should  not  appear 
more  than  once  in  the  same  list ;  that  is,  that  each  list  should 
furnish  lOO  different  words.  It  is  possible  that  this  last  require- 
ment may  have  been  a  deviation  from  Professor  Jastrow's 
method.  Upon  inquiring,  he  wrote  me  that  he  was  not  certain 
whether  the  Wisconsin  lists  had  been  kept  free  from  repetitions 
or  not.  With  a  very  few  exceptions,  the  same  word  does  not 
appear  twice  in  any  one  paper  in  the  California  lists.  Having 
selected  the  lists,  the  words  of  each  set  were  then  separately 
tabulated  under  the  following  twenty-five  heads,  the  words 
written  by  the  men  and  women  being  kept  apart  in  each  set : 
(i)  animal  kingdom,  (2)  verbs,  (3)  proper  names,  (4)  adjec- 
tives, (5)  implements  and  utensils,  (6)  abstract  terms,  (7)  wear- 
ing apparel  and  fabrics,  (8)  vegetable  kingdom,  (9)  building 
and  building  materials,  (10)  parts  of  the  body,  (11)  geograph- 
ical and  landscape  features,  (12)  other  parts  of  speech,  (13) 
miscellaneous,  (14)  interior  furnishings,  (15)  meteorological  and 
astronomical,  (16)  mineral  kingdom,  (17)  occupations  and  call- 
ings, (18)  conveyances,  (19)  stationery,  (20)  foods,  (21)  educa- 
tional, (22)  arts,  (23)  amusements,  (24)  mercantile  terms,  (25) 
kinship. 

After  classifying  each  of  the  three  sets  separately,  they 
were  then  combined  and  the  set  thus  obtained  consisting  of 
seventy-five  men's  lists  and  seventy-five  women's  lists,  was  clas- 
sified as  the  smaller  sets  had  been. 

The  division  of  the  words  under  the  above  twenty-five  heads 
follows  the  classification  of  Dr.  Jastrow  in  order  that  the  Cali- 


UNREFLECTIVE   IDEAS    OF  MEN  AND    WOMEN.  52 

fornia  results  might  be  comparable  with  those  of  Wisconsin, 
although  certain  objections  to  the  division  might  be  urged.     For 
example  it  might  be  pointed  out  that  the  procedure  of  Dr.  Jas- 
trow  does  not  admit  of  exact  repetition,  though  this  is  essential 
to  a  correct    testing    of   results.     No  two  experiments   would 
tabulate  the  words  in  the  case  of  the  twenty-five  classes  under 
exactly  the  same  heads.     This  difficulty  arises  from  the  fact 
that  some  of  the  classes  are  vague.     An  illustration  of  this  lack 
of  clear  definition  may  be  drawn  from  the  class  *  interior  fur- 
nishings.'    Many  of  the  household  articles  that  women  use,  are 
of  course,  'implements  and  utensils  '  and  just  what  household 
articles  should  be  classed  as  '  interior  furnishings '  and  what  as 
*  implements  and  utensils '  is  not  clear.     In  case  most  of  the 
implements  women  use  about  their  work  are  classed  as  '  interior 
furnishings,'  the  preponderance  of  the  men  in  the  implement 
group  loses  all  its  significance.    The  class  '  foods '  is  not  clearly 
to  be  distinguished  from  the  '  animal,'  '  vegetable  '  and  '  mineral 
kingdom '  groups,  since  all  foods  can  be  classed  under  these 
three  heads.     Here  again  there  is  a  chance  for  words  to  stray. 
The  class  '  educational '  is  also  exceedingly  vague.     Each  per- 
son who  uses  this  system  of  classification  will  probably  classify 
under  this  group  somewhat  differently.     The  personal  factor 
will  come  in  to  an  appreciable  extent  in  each  repetition  of  the 
experiment    and    absolute    uniformity  of   method  will   not   be 
secured. 

These  defects  are  easier  to  see  than  to  remedy.  If  a  classi- 
fication free  from  them  is  possible,  it  must  probably  be  made 
along  more  strictly  logical  lines.  The  words  would  need  to  be 
classified  several  times  instead  of  once,  selecting  in  each  classi- 
fication some  one  principle  of  division. 

In  two  cases,  I  have  made  slight  changes  in  Dr.  Jasrrow's 
terminology.  For  his  term  '  unique  words,'  unrepealed  zvords 
has  been  substituted,  and  for  the  term  '  different  words,'  vocab- 
ulary has  been  used. 

In  Table  A  the  results  of  the  California  experiments  are 
given,  together  with  those  previously  reported,  arranged  in 
the  order  in  which  the  experiments  were  performed. 

To  aid  in  comparing  the  results,  they  have  been  represented 


53 


GENEVIEVE   SAVAGE  MANCHESTER. 


< 


a 

CJ 

M 

t~^  lOCO 

o 

O- 

lO 

CO  ^^  t^SO 

CO  M 

COO 

lO  Ost^  ii->  CO  O 

'*•* 

t-^ 

1 

—^  o 

0 

VC   0    0\rOrOP<   ■^CN    rOTt^tiorO  ■^VO   l^  rf  C    O  CO   I^vo   I^  t^  lO 

2^ 

•St« 

lOrOt^MMTTi-cCMPirocsrr)              (NMioi-irO'-iM'-ifNJ^fD 

fl  c4 

c 

CS    0   •*  ICVD   rOrOt^MVO   ■*i-'00    0^^~•r^^l   >-i   »OtM   rOr^CTMOiO 

OS 

"s 

OJ 

"*  Tt  M    t^  t^VO    ror^-^O    -^t^CS    rO  lOCO    ONCO    N    t^  lO  t^  -^  G    -^ 

OS 

S 

VD    rovo         McOMMCtrontN               tsdiOi-ifOMCti-iMa^Cl 

■^ 

r^ 

in 

vD  i-i  0  r^  r--.vD  ONoioo  0  CT^n  mco  o^o  ro-^  ■^vo  '-'  0^  ij  ^  tr 

8 

S  >- 

0 

•5  t; 

MMCO                                     1-1                      M(N                      MMI-I                              MCS 

lO 

^ 

& 

w 

0   i-i  fO  I'i  10  TtOO  10  1/5  fO  ro  t^vO  ^^Ol-''-|'^OT^|-'l-'00^^^ 

o 

W 

0 

j-^  t^oo  Tti^'^iouo'3-N  0  •^i-i  i-i  >-  t^'O'^ON'o  ^00  o>  o>  •-' 

o 

U 

MP)                     M                              MWM                     MHC                                                        MM 

lO 

.2 

a 

^ 

M 

11 

B 

0   MVD    rOU-jO   M   0   tOrOTtCT^'^J-M    w    OOOVO   cOOO  VO  00   fO  O  VO 

o 

i2 

11 

MlO-CSt^MlOT)  lOOO    ■*  W    M    CI    OS  CT^OO    t^  M    ID  lO  t^  >OVO  CO 

o 

"3 

s 

piOtlH                                       MM                                       MM                                       CO 

M 

0 

d 

VD   •'*•  t^  M   Tt  lOOO  t^  M  VD    CT\CO   M   uo  OS  OS  ■*  M   ro  moO  t^OO  CO  CO 

o 

a 

OS  M   Tt  lOOO   -^  -^  OsCO   M    OS  r<    M   M   Qs\0    rOrni-^r^<N   ■^t^M   m 

o 

.2 

"S 

u 

MMM                        M                                  MM                                           M                                  M                        MM 

in 

M 

£ 

ri 

0^  CN)   M   t^  Trj-vO   O    OS  »0  O   ■*C0   Tt  t-»  M   OS  t^OO   O   M    CTM-^  0\  OS  O 

8 

u 

tn  \n  o  (^  in  —  -^  looo  mmi^           oO'^ioosMOsioosiot^ 

"3 

§ 

MMN                        M                                  MM                                 MMM                        M                                 0) 

M 

M 

VD   t^r^OsO\M   mOsOs'^iON    Osm   rOfOiOOsO   OSO   ION   t^O 

\     r-- 

4^ 

B 
0 

OS  M  V£)   PO  t^  CO  '^VO    O   O   •^00         M   lO  rO  lO  CO  '^"O   O   cO  O   lO  m 

OS 

a; 

Kmn                m                mm                                        pimmmmm 

M 

"S 

u 

^ 

!§ 

a 

cOt^t^iOt^-r^OOO   ■*  COVD   "*  O    O   -^OO   t-^  t^  M   W  CO  CO   t-.SO    O 

'    2^ 

u 

OS  CO  O   N   -^  <N   -^SD   O   MOOVO   M   MVDOO   "T^J-m   OsOscO  O^00  00 

OS 

0 

s 

MMPIMMM                                                       MM                                      M 

•<* 

M 

a 

00r-»NcOMt^(SVCOsOt-iOM   OsvO  V£)   t^  l^  >0  lO  cOV£)    O   ■'^f  'S 

■    9 

i 

t^  OS  O   lOVD   M   lo  «>•  1-^00   MOscOMt^OSOS'*        O   lOOO   m   co  01 

o 

c' 

MM                     M                     MMM                                                                H1MMMM 

lO 
M 

'55 

s 
0 

^ 

to 

C 

■^M   t^O   cOiON   '^cOt^OsOsf^O   lO'^M   1-ivD   M   rJ-O    M   t^O 

^   8 

% 

OJ 

lOrOt^cOcOOvO   rouo  OssD  CO   m   cOOO   t-^  OS  r~-  Os  O   OS^O   O    Os  CN 

s 

MMM                           M                                                M                                                                                           ^,„MMM 

M 

</ 

"k 

'w 

15 

o 

CJ 

s 

o 

c. 

rt 

fc 

s 

''3     ; 

O    "5 

1 

jd 

be 

IT  t/5  be 

B) 

B 

s 

c 

"'S 

c  c  c 

s"  *  e 

S^-  o 

c 
W) 

"a 

O   VI 

»-r 

_  D    t« 

V-    C8  T!    en 

t«  ?  t/i' 

c 

n 

.s  a  (/ 

il 

ngs,  bui 
yances. 
tional  . 

aphical 
mcuts, 
Dr  furni 

utile  te 
irologic 
al  kingi 
llaneou 
ations . 
parts  o 
of  the  h 
r  name; 

3 

c 

Cl 

b 

JO      « 

■       a 

*  ,*  t^  S 

:■- i(UcStnwi(u..-_acOO^injCi.i-.         on^^tnT 

I      2 

- 

i    C 

•<  t 

h^ 

i  li 

O^ 

5  r 

^CK 

5  c 

M     >■ 

■4     h 

^    c 

O': 

■t     H 

t  li 

Ovi 

t   (- 

3  r 

^« 

5  c 

5  •- 

>  c 

i  p 

i- 1 

o 

UNREFLECTIVE   IDEAS    OF  MEN  AND    WOMEN. 


54 


graphically  by  a  system  of  vertical  lines,  the  lengths  of  which 
are  proportionate  to  the  numbers  given  in  Table  I.  The  con- 
tinuous lines  represent  the  number  of  words  in  each  class  used 
by  the  men,  the  broken  lines,  the  number  of  words  written  by 
the  women. 

The  order  of  arrangement  of  the  classes  in  the  diagram  is, 
of  course,  arbitrary.  For  convenience,  the  classes  are  arranged 
in  the  order  of  their  size,  as  obtained  in  the  results  of  Professor 
Jastrow's  men.     The  series  begins  with  the  class  '  animal  king- 


'S«6 


£40 


TABLE   I. 

University    of  Wisconsin. 

Continuous  lines Men. 

SroJfcn  lines Women. 


u 


U—k. 


fn 


It 


I  i  1^1  lit  3 


^  .? 


fs:  ^ 


-J'  >^  ^  ■;;:  f^  ^"^  5  ^^ 

1 1 1 1 3  ^^  •*  i-*3 


r»s  "    ?» 


1$   ■"5)'^^ 


(^    K    ^    1    ^ 


<:i    <o    «>) 


•5  & 


J^^ 


.9. 


^  ^ 


dom,'to  which  the  men  of  the  Universit}'  of  Wisconsin  contrib- 
uted the  largest  number  of  words,  and  ends  with  '  kinship,'  the 
class  to  which  they  gave  the  smallest  number  of  words.  This 
order  is  kept  for  the  women  of  the  Wisconsin  lists  and  for  all 
the  subsequent  lists. 

Turning  now  to  Table  I.  to  review  the  com;  arison  of  the 
Wisconsin  men  and  women,  it  is  seen  at  a  glance  that  the  women 
greatly  preponderate  over  the  men  in  the  class  of  '  wearing  ap- 
parel and  fabrics,'  '  interior  furnishings  '  and  '  foods  ' ;  to  a  less 
degree  in  the  classes  '  educational,' '  arts  '  and  '  amusements.'   In 


55 


GENEVIEVE   SAVAGE  MANCHESTER. 


mentioning  terms  denoting  objects  in  the  '  animal  kingdom,' '  ad- 
jectives,' 'abstract  terms'  and  'implements  and  utensils,'  the 
men  exceed  the  women.  Numerous  other  variations  are  shown, 
but  these  are  the  most  striking. 

A  comparison  of  these  results  with  those  obtained  by  the  Cali- 
fornia experiments  discloses  the  fact  that,  while  there  is  general 
agreement  in  several  interesting  particulars,  there  is  nothing 
that  can  be  called  complete  corroboration  of  the  conclusions 
Professor  Jastrow   drew.  ^     A   prominent   characteristic   to   be 


180- 


TABLE  II 
Uninrsity  of  California ,  stt  1. 

ConHnuous  lines /Hm. 

,  Broken  linet Women. 


I 

•It 


Is 


•^1 


?   >^ 


<•'    W 


J    t* 


«i 


f5 1 1  ^ 


^ 


.?    ^     ?.    '^ 


tj    ij     k 


noted  in  the  California  experiments  is  the  absence  of  the  marked 
disparity  between  the  men  and  women  which  the  Wisconsin 
record  shows.  In  the  class  *  wearing  apparel  and  fabrics,'  the 
California  women  clearly  exceed  the  California  men  but  in  a 
less  degree  than  the  Wisconsin  women  exceed  the  Wisconsin 
men.     (Compare  Tables  II.,  III.,  IV.  and  V.  with  Table  I.) 

The  same  relation  holds  for  the  class  '  interior  furnishings  ' ; 
but  in  the  case  of  '  foods,'  one  of  the  three  classes  in  which  the 

^The  fact  that  there  are  no  men's  lists  in  the  Wellesley  material  is  an 
obvious  drawback  in  comparing  them  with  Wisconsin  and  California  lists  and 
for  that  reason  they  will,  for  the  time,  be  left  out  of  account. 


UNREFLECTIVE  IDEAS    OF  MEN  AND    WOMEN. 


56 


Wisconsin  women  markedly  exceeded  the  Wisconsin  men,  the 
result  differs  from  that  obtained  by  Professor  Jastrow.  In  one 
of  the  California  sets,  the  women  exceed  the  men  slightly  (see 
Table  II.),  while  in  the  other  two  sets,  the  men  are  slightly 
in  advance  of  the  women. 

The  California  lists  agree  with  the  Wisconsin  lists  in  that  the 
women  exceed  the  men  in  the  classes  '  educational,'  '  arts,'  and 
'  amusements ' ;  but  as  before,  the  California  men  and  women 
differ  less  from  each  other  than  the  Wisconsin  men  and  women. 


3S0T 


300 


240 


l»0- 


ISO 


60- 


TABLE  m. 
Unhersity  of  California,  Sei  S. 

Continuous  iines Men. 

Broken  lines Women. 


% 

^ 


5    .,   J 


"S     5     V) 


—.VIA 


:s:   f>,   ^ 


«<    «s    3; 


1!| 

•Si?.*? 


i_ii 


I!  il 


*    !■  1. 


-u. 


5   ,0 


$$i=i  ^^e^k 


?  <  ^ 


.^ 
•$ 


The  notable  ratios  in  which  the  Wisconsin  men  exceeded  their 
women  classmates  in  terms  belonging  to  the  classes  '  animal 
kingdom,'  '  proper  names '  and  '  adjectives '  do  not  hold  for  the 
California  lists.  The  California  sets  all  agree  with  the  Wis- 
consin lists  in  that  the  men  lead  the  women  in  every  case  in 
mention  of  'verbs'  and  'implements  and  utensils.'  A  general 
agreement  of  both  Wisconsin  and  California  results  is  to  be 
found  in  the  fact  that  both  men  and  women  drew  the  larger  part 
of  their  words  from  the  classes  arranged  on  the  left  half  of  the 
tables,  while   the  classes  to   the   right,  such  as  '  educational,' 


SI 


GENEVIEVE   SAVAGE  MANCHESTER. 


*  amusements,'  '  mercantile  terms  '  and  especially  '  kinship  '  fur- 
nish comparatively  few  of  the  surface  ideas. 

In  the  Wisconsin  lists,  Dr.  Jastrow  found  that  the  vocabulary 
of  the  men  was  greater  than  that  of  the  women.  The  same  re- 
sult was  obtained  in  all  three  of  the  California  sets.  In  Table 
VI.  the  results  of  this  part  of  the  experiment  are  tabulated,  the 
results  of  the  Wisconsin  and  Wellesley  experiments  being 
included.  ^ 


lao 


\1 


il 


TABLE  IV, 
University  of  CatiforniaSdi^. 


Continuous  lines . 
3rokeft  7ir:ss. .  . 


.  . .  Men. 
Women. 


I  I 
I 

I  I 

J  ' 


I    I 


\l\'  It 


55 


5 

i.    ft.  «^ 


I    I 

I-  * 


i:'*^  3^'5  r^^  ? 


•f'^'  § 


5 
,,5 


i  ^  ttj 


J5  «2 


^1 


§•   ^    -5 


-6     -5 


^    ^    Q    <0    "o    k 


•4     S 
§1 


1^ 


.5. 


A  study  of  this  table  shows  that  in  each  of  the  five  sets,  the 
men  have  used  a  larger  percentage  of  different  words  than  the 
women  of  the  same  set.  In  set  II.  of  the  California  series,  how- 
ever, the  women  exceed  the  men  of  set  I.  in  vocabulary.  It  is 
to  be  remarked  that  the  women  in  all  three  of  the  California  sets 
and  also  in  the  Wellesley  set,  exceed  the  Wisconsin  men  in 
vocabulary.  It  is  also  to  be  noted  that  the  difference  between 
the  vocabularies  of  the  Wisconsin  men  and  women  is  considera- 
bly greater  than  that  between  the  California  men  and  women. 

'  The  column  headed  '  percentages  '  indicates  the  ratio  of  the  vocabulary  to 
the  total  number  of  words  written. 


UNREFLECTIVE   IDEAS    OF  MEN  AND    WOMEN. 


5S 


The  vocabulary  of  the  Wisconsin  men  is  lO  per  cent,  larger 
than  that  of  their  women  classmates,  while,  in  no  case,  does  the 
vocabulary  of  the  California  men  exceed  that  of  the  California 


90» 


726- 


itO 


I       i 


I 


1 

lJjl. 


TABLE  V. 

Oft/versify  of  Csfifornia,  Canbined  Sets. 

Cmtinusui  H.^es Men. 

Braken  liaai .  Wame.t. 


!«     e 


'    M    V*    h 


I  \ 


I    il 

IJi. 


•^    ii'    K 


St  V  ^o     -^-r     4^ 

pi 


^  js>  ■•■> 


^  ^ 


i^   U    s:^    ^^   < 


.sj' 

"5 


$    ^ 


k  1^ 


women  more  than  4  per  cent.  In  every  set,  both  the  men  and 
women  in  the  California  experiment  use  larger  vocabularies 
than   either   the   men   or  women    of  Wisconsin.     It  would,  of 

Table  VI. 


Unrepeat 
Men. 

ed  Words. 
Women. 

Vocabulary. 

Percentages. 

Men. 

Women. 

Men. 

Women. 

Wisconsin 

746 
1000 
117a 
1079 
1975 

520 

949 

1079 

978 

1950 
868 

1376 
1471 
1583 
1489 

3119 

II23 
1397 
1509 
1407 
3C48 
1306 

55 

58 

63-32 

59-56 

41.58 

44-9 

55-9 

60.36 

56.28 

40.64 

52.25 

California  Set  I 

California  Set  II 

California  Set.  Ill 

Combined  Calif.  Set. 
Wellesley 

course,  be  unwarranted  to  conclude  from  these  results  (though 
the  thought  is  at  least  suggested)  that  the  men  and  women  of 
California  have  more  diversified  interests  that  those  of  Wiscon- 


59  GENEVIEVE   SAVAGE  MANCHESTER. 

sin,  and  that  the  men  and  women  of  California  differ  from  each 
other  less  than  the  men  and  women  of  Wisconsin.  Only  one 
set  of  lists  is  given  here  for  the  University  of  Wisconsin,  and 
additional  sets  might  change  the  proportions  materially.  The 
matter  of  the  treatment  of  plurals  may  account  in  great  part  for 
the  larger  vocabularies  obtained  in  the  California  experiments. 
I  have  in  all  cases  counted  the  singular  and  plural  of  the  same 
idea  as  two  different  words.  The  justification  for  this  is  to  be 
found  along  psychological  rather  than  etymological  lines. 
Etymologically,  the  words  horse  and  horses  are  practically  the 
same,  but  the  mental  picture,  or  idea,  corresponding  to  each  is 
different.  If  Professor  Jastrovv  did  not  make  this  distinction, 
but  counted  the  singular  and  plural  forms  of  an  idea  as  the  same 
word,  the  vocabularies  in  the  Wisconsin  study  would  be  corres- 
pondingly low. 

That  the  men  exceed  the  women  in  vocabulary  in  each  of  the 
five  sett?,  is  significant,  even  if  the  superiority  on  the  part  of  the 
men  is  slight.  It  should  be  remembered  that  in  the  combined 
California  set,  the  total  number  of  words  was  three  times  as 
large  as  in  the  other  sets.  It  is  to  be  noted,  further,  that  not  only 
the  percentage  of  difference,  but  the  absolute  difference  between 
the  vocabularies  of  the  men  and  women  is  greater  in  the  2,500- 
words  sets  than  in  the  7,500-word  set.  In  the  smaller  sets,  the 
difference  varies  from  two  per  cent,  to  a  little  more  than  three 
per  cent,  while  in  the  large  set,  the  difference  is  leveled  to  one 
per  cent.  It  seems  likely  that  if  the  number  of  lists  were  in- 
definitely increased,  the  difference  in  vocabulary  between  the 
men  and  women  would  diminish  regularly  as  the  limits  of  the 
language  were  approached. 

Leaving  now  any  further  comparison  of  the  California  re- 
sults with  those  obtained  by  other  experiments,  a  more  profita- 
ble field  for  study  lies  in  the  examination  of  the  cumulative  re- 
sults of  the  experiments  at  Wisconsin  and  California,  in  order 
to  discover  in  what  features,  if  any,  all  of  the  results  agree.  If 
this  study  is  to  disclose  any  real  differences  between  the  unre- 
flective  ideas  of  the  sexes,  such  differences  should  be  evident  in 
all  of  the  sets  of  lists,  or  at  least  in  a  pronounced  majority  of 
them.     The  most  significant  differences,  then,  revealed  by  these 


UNREFLECTIVE   IDEAS    OF  MEN  AND    WOMEN. 


60 


experiments,  will  be  those  which  appear  in  every  one  of  the 
four  sets. 

To  indicate  the  agreement  or  disagreement  of  the  different 
sets  as  regards  the  classes  of  words  used  Table  VII.  was 
prepared. 

Table  VII. 
+  Me;n  Lead.     — Women  Lead. 

Calif.  Comb. 


Animal  kingdom 

Verbs 

Proper  names 

Adjectives 

Implements  and  utensils 

Abstract  terms  

Wearing  apparel,  fabrics 

Vegetable  kingdom 

Buildings,  building  materials 

Parts  of  body 

Geographical,  landscape 

Other  parts  of  speech 

Miscellaneous 

Interior  furnishings 

Meteorological, astronomical 

Mineral  kingdom 

Occupations , 

Convey  ances 

Stationery 

Foods 

Educational 

Arts,  sciences 

Amusements 

Mercantile  terms 

Kinship 


Wis. 

Calif.  I. 

Calif.  II. 

Calif.  III. 

+ 

— 

+ 

+ 

+ 

+ 

+ 

-L. 

+ 

— 

— 

+ 

+ 

— 

— 



+ 

+ 

+ 

+ 

_L 

+ 

+ 



+ 

— 

+ 

— 



+ 

+ 

+ 

+ 

+ 

— 



+ 

— 

+ 

+ 



-4- 

+ 

+ 

+ 

+ 

+ 





+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

— 

— 





+ 

+ 

— 

— 

— 

+ 

+ 

+ 

— 

+ 

+ 

— 

— 

+ 
+ 


+ 
+ 


+ 

+ 
+ 


+ 
+ 


+ 


In  this  table,  the  classes  in  which  the  men  excelled  the 
women  in  the  number  of  words  written  are  marked  by  a  plus 
sign,  while  the  classes  in  which  the  women  led  are  indicated  by 
a  minus  sign. 

A  review  of  the  results  of  the  classification  into  the  twenty- 
five  groups,  shows  a  rather  remarkable  agreement  in  the  five 
sets  tabulated  in  Table  VII.  Of  the  twenty-five  classes,  eigh- 
teen show  an  agreement,  either  in  all  five  cases  or  in  four  cases 
out  of  five.  In  the  three  classes  in  which  the  men  lead  most 
pronouncedly,  namely,  in  '  verbs,' '  implements  and  utensils  '  and 
*  occupations,'  the  notion  of  action  is  prominent.  In  the 
classes  in  which  the  women  lead,  such  as  '  adjectives,'  '  wear- 
ing apparel  and  fabrics,'  'interior  furnishings'  and  'buildings 


6l  GENEVIEVE   SAVAGE   MANCHESTER. 

and  parts  of  buildings,'  no  such  notion  is  evident.  On  the  con- 
trary, these  show  a  preference  for  things  at  rest. 

Running  through  all,  or  nearly  all,  of  these  agreements  in 
results,  there  appears,  beside  the  notion  of  action  as  contrasted 
with  inaction,  another  element.  In  the  cases  in  which  the  men 
lead,  time  is  an  essential  factor ;  in  the  cases  in  which  the 
women  lead,  space  is  the  more  prominent  consideration.  While 
the  time  and  space  conceptions  are  closely  allied  to  the  notions 
of  action  and  inaction,  they  seem,  nevertheless,  to  be  not  alto- 
gether identical.  A  further  inference  may  be  drawn  from  the 
cases  in  which  there  is  agreement  in  all  five  sets.  The  fact 
that  the  men  throughout  draw  a  large  percentage  of  their  words 
from  such  classes  as  'implements  and  utensils,'  'occupations,' 
and  '  verbs '  than  the  women  do,  and  from  the  fact  that  the 
women  lead  throughout  in  the  classes  '  wearing  apparel  and 
fabrics,'  '  buildings  and  building  materials,'  and  '  interior  fur- 
nishings,' it  may  be  inferred  that  the  unreflective  ideas  of  both 
men  and  women  concern  the  objects  with  which  they  are  famil- 
iar and  in  which  they  have  considerable  interest.  That  the 
classes  '  implements  and  utensils  '  and  '  occupations '  are  of 
special  masculine  interest,  will  probably  not  be  questioned,  but 
such  an  interpretation  of  the  verb  class  needs  justification.  This 
justification  is  found  in  the  character  of  the  verbs  used.  In  a 
ver}^  large  percentage  of  the  cases  in  which  men  use  verbs, 
these  verbs  are  suggestive  of  action  in  the  field  of  men's  es- 
pecial interest. 

To  make  this  clear,  two  lists  of  verbs  are  submitted,  one  se- 
cured from  three  men's  papers  and  the  other  from  three  women's, 
the  lists  being  taken  at  random  in  both  cases.  Such  words  as 
'  address '  and  '  telegraph,'  classed  here  as  verbs,  may  also  be 
nouns.  In  such  cases  the  context  was  taken  as  a  guide  in  de- 
termining the  sense  in  which  the  writer  used  the  word.  The 
lists  follow  : 

A.  (i)  address,  (2)  telegraph,  (3)  fall,  (4)  rise,  (5)  call,  (6) 
forget,  (7)  ride,  (8)  play,  (9)  ringing,  (10)  reading,  (11)  study- 
ing, (12)  work,  (13)  play,  (14)  tick. 

B.  (i)  shoot,  (2)  tick,  (3)  twitch,  (4)  cure,  (5)  hit,  (6)  miss, 
(7)  aim,  (8)  blow,  (9)  shoot,  (10)  sail,  (11)  hoist,  (12)  lift,  (13) 
pump,  (14)  rush,  (15)  study,  (16)  judge. 


UNREFLECTIVE   IDEAS    OF  MEN  AND    WOMEN.  62 

The  first  series  of  verbs  was  taken  from  women's  lists,  the 
second  from  men's.  The  masculine  character  of  the  second 
series  is  unmistakable  and  was  so  judged  by  several  persons  to 
whom  the  lists  were  read  without  disclosing  the  actual  source  of 
each  group. 

With  this  further  knowledge  of  the  verbs  used,  it  seems  safe 
to  say  that  the  evidence  justifies  the  statement  that  the  un- 
reflective  ideas  of  men  are  controlled  by  the  familiar  and  inter- 
esting acts  and  objects  of  their  lives.  Similiarly,  the  classes 
'  wearing  apparel  and  fabrics,'  and  '  interior  furnishings,'  are 
recognized  categories  of  peculiar  feminine  interest.  It  might 
be  suggested,  however,  that  buildings  and  building  materials 
are  not  distinctly  familiar  and  interesting  to  women.  The  ob- 
jection falls  when  the  character  of  the  words  drawn  from  this 
class  is  known.  The  words  used  were  names  of  particular 
buildings  and  parts  of  houses,  such  as  court  house,  church, 
gate,  door,  floor,  fence,  steps,  marble.  There  is  scant  men- 
tion by  the  women  of  such  distinctive  building  materials  as 
bricks,  mortar,  cement  and  stone. 

Just  why  women  should  exceed  men  in  the  classes  '  arts,' 
and  '  educational '  is  not  evident,  but  taking  the  cue  from  the 
former  cases,  it  seems  that  it  might  be  because  these  classes  of 
objects  are  more  familiar  to  women  than  to  men  and  of  rela- 
tively more  importance  to  them.  Though  men  are  the  chief 
creators  of  art,  women  are  more  familiar  with  the  ordinary  art 
products,  such  as  pictures  and  musical  compositions.  Simi- 
larly in  educational  matters,  the  women  were  probably  more 
impressed  with  the  parts  of  the  educational  system,  such  as  lec- 
tures, texts  and  examinations,  owing,  perhaps  to  the  fact  that 
many  of  them  were  preparing  to  become  teachers. 

That  the  women  lead  in  the  category  of  amusements,  is 
probably  due  to  the  fact  that  women,  as  a  class,  have  more 
leisure  than  men.  With  the  time  to  enjoy  amusements  of  vari- 
ous kinds,  women  indulge  more  in  them.  Hence  these  things 
are  more  familiar  to  women  than  to  men  and  come  more  read- 
ily to  mind  when  there  is  a  call  for  a  rapid  gathering  of  ideas. 

Leaving  now  the  cases  where  there  is  an  agreement 
throughout  all  five  sets,  the  agreements    which   appear  in   four 


63  GENEVIEVE   SAVAGE   MANCHESTER. 

sets  out  of  five  deserve  a  word.  In  the  classes  '  animal  king- 
dom,' '  abstract  terms,'  '  parts  of  the  body,'  '  miscellaneous,' 
'  mineral  kingdom  '  and  '  other  parts  of  speech,'  the  men  exceed 
the  women  in  four  sets  out  of  five.  The  mention  of  objects  be- 
longing to  the  '  animal  kingdom  '  is  plentiful  in  the  lists  of  both 
men  and  women,  the  difference  between  the  number  of  times 
such  words  are  written  by  men  and  women  being,  on  the  whole, 
not  very  large,  but  the  fact  is  notable  that  in  all  cases,  but  one, 
the  sex  naturally  most  familiar  with  the  various  members  of  the 
'  animal  kingdom  '  is  the  one  which  leads  in  this  class.  In  the 
class  '  abstract  terms,'  a  similar  condition  prevails.  While  the 
total  numerical  lead  of  the  men  over  the  women  is  not  great,  it 
is,  nevertheless,  to  be  found  in  four  cases  out  of  five.  That 
men  have  more  interest  and  training  in  mathematical,  physical 
and  philosophical  abstractions,  might  account  for  this  difference. 
The  significance  of  the  men's  lead  in  mention  of  '  other  parts  of 
speech '  is  not  clear.  In  the  classification  used,  this  term  em- 
braces conjunctions,  prepositions,  interjections,  pronouns  and 
adverbs.  Since  the  class  was  not  subdivided,  it  is  impossible 
to  tell  in  which  of  the  four  parts  of  speech  the  men  markedly 
excel.  As  they  lead  in  verbs,  it  might  be  expected  that  they 
would  lead  in  adverbs.  So  too,  it  might  be  expected  that  men 
would  lead  in  prepositions  and  conjunctions  since  these  deal 
with  abstract  relations. 

Men  also  lead  the  women  four  times  out  of  five  in  mention 
of  '  parts  of  the  body.'  Just  what,  if  anything,  this  implies,  I 
have  not  determined,  though  it  may  be  that  the  greater  impor- 
tance of  the  parts  of  a  man's  body,  as  tools  for  his  daily  use, 
keeps  the  conceptions  of  them  more  constantly  in  his  mind. 

That  men  lead  in  the  class  '  miscellaneous '  may  mean  any 
one  of  several  things.  If  the  other  groups  in  the  classification 
happened  to  be  more  adapted  to  catch  the  surface  ideas  of  women 
than  those  of  men,  the  '  miscellaneous '  class  would  be  corre- 
spondingly large  for  the  men.  Another  explanation  of  the 
men's  superiority  here  might  lie  in  the  fact  that  men  are  inter- 
ested in  a  greater  number  of  objects  and  activities. 

The  lead  of  the  men  in  the  '  mineral  kingdom  '  is  probably 
due  to  the  fact  that  they  carve  and  chisel,  mine  and  build,  while 
women  ordinarilv  do  not. 


UNREFLECTIVE   IDEAS    OF  MEN  AND    WOMEN.  64 

'  Conveyances  '  might  have  been  discussed  under  the  head  of 
*  amusements,'  as  most  of  the  words  in  this  class  seemed  to  be 
of  that  general  character. 

That  the  women  in  all  of  the  California  sets  lead  in  the  men- 
tion of  adjectives  seems  significant.  It  has  been  found  in  the 
classes  discussed  before  that  the  surface  ideas  of  men  concern 
action,  the  tools  used  in  the  performing  acts,  and  the  differentia- 
tions of  particular  acts  into  occupations;  that  is,  their  ideas  are 
related  to  construction.  The  women,  on  the  other  hand,  excel 
the  men  in  the  mention  of  articles  of  dress,  house  fittings,  parts 
of  houses,  particular  buildings  and  art  products.  There  seems 
to  be  a  real  principle  of  difference  herein  the  general  character 
of  the  words  written  by  the  men  and  those  written  by  the  women. 
Men  speak  of  the  process  of  creating,  women  of  the  thing 
created.     This  is  the  same  conclusion  reached  by  Dr.  Jastrow. 

In  view,  then,  of  this  tendency  of  the  feminine  mind  toward 
things,  rather  than  the  doing  of  things,  it  seems  natural  that 
women  should  be  more  familiar  with  the  qualities  of  things  than 
men  are.  This  preponderance  of  adjectives  in  the  women's 
lists  seems  to  bear  out  this  supposition. 

In  the  mention  of  terms  of  kinship,  it  is  of  interest  to  note 
that  both  the  men  and  the  women  draw  very  sparingly  from  this 
class.  This  fact  seems  rather  in  opposition  to  the  hypothesis  be- 
fore advanced  that  the  surface  ideas  are  of  things  familiar  and 
interesting,  for  of  course  one's  kindred  are  usually  the  persons 
seen  oftenest  and  considered  of  greatest  importance.  It  is 
probable  that  unconscious  or  even  conscious  selection  played  a 
part  here.  It  is  very  likely  that  the  persons  writing  the  lists 
considered  this  work  a  sort  of  official  act  since  the  papers  were 
to  be  returned  to  an  instructor,  and  they  would  naturally  refrain 
to  a  certain  extent,  from  speaking  of  parents  and  other  relatives. 
The  very  attitude  the  mind  took  in  performing  the  task  would 
inhibit  ideas  drawn  from  the  family  life. 

In  the  classes  which  have  not  yet  been  discussed,  '  proper 
names,' '  meteorological  and  astronomical  terms,' 'stationery,' 
'  foods  '  and  '  mercantile  terms,'  there  is  not  enough  regularity 
to  warrant  the  drawing  of  any  conclusions.  In  the  class  '  proper 
names,'  it  would  be  expected  that  the  women  would  lead  con- 


65 


GENEVIEVE   SAVAGE  MANCHESTER. 


siderabl}',  since  they  show  a  preference  for  the  concrete,  rather 
than  the  abstract,  but  in  two  sets  out  of  five,  the  men  are  ahead. 
Again,  the  natural  expectation  would  be  that  men  would  write 
many  more  astronomical  and  meteorological  terms  than  women, 
but  in  this  class  the  men  lead  in  only  three  cases  out  of  five. 
Oddly  enough,  the  men  on  the  whole,  in  the  California  sets, 
lead  slightly  in  foods,  and  the  women  in  mercantile  terms,  very 
different  results  from  those  obtained  by  Dr.  Jastrow. 

Coming  now  to  the  last  feature  to  be  examined,  namely,  the 
time  required  to  write  the  lists,  it  is  seen  from  Table  VIII.  that 
the  average  time  for  the  women  of  California  is  5  minutes  and 
39  seconds.  The  average  time  for  the  men  of  California  is  5 
minutes  and  47  seconds. 

Table  VIII. 


Average  for  Men. 

Average  for  Women. 

Average  for  Men 
and  Women. 

6  min.      2  sec. 
6  min.     17  sec. 
5  min.     2j^  sec. 

5  min.     47  sec. 

6  min. 

5  min.     55  sec. 

5  min.     2  sec. 

5  min. 

5  min.     39  sec. 

5  min.     8  sec. 

6  min.     i  sec. 

California  I 

California  II 

California  III 

Wellesley  

6  min.     6  sec. 
5  min.     2  sec. 

Combined  Calif.  ... 

As  Professor  Jastrow  does  not  give  the  average  time  for  each 
sex  separatel}'",  and  as  there  are  no  men  in  the  Wellesley  list, 
these  sets  are  not  available  for  this  comparison. 

In  each  of  the  California  sets,  the  time  the  women  required 
to  write  the  lists  is  slightly  less  than  that  of  the  men.  This 
may  mean,  either  that  the  women  associate  more  quickly,  or 
that  they  write  more  rapidly.  That  each  student  kept  his  own 
time  renders  these  results  less  trustworthy  than  they  would 
otherwise  have  been. 

Having  now  presented  the  evidence  at  hand,  it  only  remains 
to  review  the  differences  in  the  unreflective  ideas  of  the  sexes 
as  suggested  by  these  experiments. 

From  the  results  of  the  classification  into  the  twenty-five 
groups,  the  following  general  statements  in  regard  to  the  surface 
ideas  of  men  and  women  may  be  made  : 

I.  The  surface  ideas  of  both  men  and  women  pertain  to  ob- 
jects which  are  familiar  and  interesting. 


UNREFLECTIVE   IDEAS    OF  MEN  AND    WOMEN.  66 

2.  The  dynamic  aspect  of  objects  is  more  attractive  to  men, 
while  the  static  or  completed  aspect  appeals  more  to  women. 

3.  Time  as  a  factor  enters  more  largely  into  the  surface 
ideas  of  men  ;  space  is  more  often  a  prominent  feature  of  the 
surface  ideas  of  women. 

4.  Men  make  a  greater  use  of  abstract  terms,  while  women 
show  a  preference  for  the  concrete  and  for  descriptive  words. 

From  the  tabulation  of  the  words  used  into  unrepeated  words 
and  vocabulary,  it  is  found  that  the  range  of  the  surface  ideas 
of  men,  as  a  group,  is  slightly  greater  than  that  of  women. 

From  the  examination  into  the  average  time  required  for 
writing  the  lists,  it  is  found  that  women  are  able  to  write  one 
hundred  associated  surface  ideas  in  somewhat  less  time  than 
men. 

All  of  the  specific  tendencies  above  mentioned  seem  to  give 
concurrence  to  a  general  principle  of  difference  between  the 
sexes.  The  surface  ideas  of  men  are  extensive  rather  than 
intensive,  while  the  opposite  is  true  of  women.  This  conclusion 
is  supported,  not  only  by  the  fact  that  men  show  a  preference 
for  abstract  terms,  for  action  and  for  the  time  idea,  while  women 
prefer  the  concrete,  the  completed  object  and  space  relations, 
but  also  by  the  facts  that  men  have  a  greater  range  of  surface 
ideas  than  women,  and  to  a  certain  extent  by  the  fact  that 
women  have  their  reflective  ideas  more  at  hand,  as  shown  by 
their  shorter  list-time.  Men  are  interested  in  far-reaching  rela- 
tions existing  between  things  ;  women  give  more  attention  to  the 
minute  analysis  of  things  themselves.' 

^  The  M3S.  of  these  Studies  were  received  October  17,  1904.  — Ed. 


OnlYersit)  of  California 

Psycliolopal  Laboratory. 


REPRINTED  FROM 

VOL.  XII.  No,  5.  September,  1905. 

THE 

Psychological    Review 

EDITED  BY 
J.  MARK  BALDWIN  HOWARD  C.  WARREN 

Johns  Hopkins  University  '^^^  Princeton  University 

CHARLES  H.  JUDD,  Yale  University  [Editor  of  the  Monograph  Series). 

WITH  THE  CO-OPERATION  FOR  THIS  SECTION  OF 

A.  C.  ARMSTRONG,  Wesleyan  University  ;  A1,FRED  BINET,  Ecole  des  Hautes- 
fiTUDES,  Paris;  W.  L.  BRYAN,  Indiana  University;  WILLIAM  CALDWELL,  Mc- 
GiLL  University;  MARY  W.  CALKINS,  Wellesley  College;  JOHN  DEWEY, 
Columbia  University  ;  J.  R.  ANGELL,  University  of  Chicago;  C.  LADD  FRANKLIN, 
Baltimore;  H.  N.  GARDINER,  Smith  College;  G.  H.  HOWISON,  University  of 
California  ;  P.  JANET,  College  de  France  ;  JOSEPH  JASTROW,  University  of  Wis- 
consin; ADOLF  MEYER,  N.  Y.  Pathol.  Institute  ;  C.  LLOYD  MORGAN,  University 
College,  Bristol;  HUGO  MONSTERBERG,  Harvard  University;  E.  A.  PACE, 
Catholic  University,  Washington  ;  G.  T.  W.  PATRICK,  University  of  Iow^a  ;  CARL 
STUMPF,  University,  Berlin;  R,  W.  WENLEY,  University  of  Michigan. 


v\^> 


THE  DIFFERENCE  BETWEEN  MEN  AND  WOMEN  IN 

THE   RECOGNITION   OF  COLOR  AND  THE 

PERCEPTION    OF  SOUND 


BY  MABEL   LORENA  NELSON, 

University  of  California. 


THE  MACMILLAN  COMPANY, 

41    NORTH   QUEEN  ST.,   LANCASTER,   PA. 

66    FIFTH    AVENUE,    NEW   YORK. 

Agent:  G.   E.  STECHERT,  London  (2  otar  Yard,  Carey  St.    W.  C); 
Lbipzig  (Hospital  St.,  :o;  Paris   (76  rue  de  Renaes). 


P?90^iciog:in3i  ^dWMv\, 


[Reprinted  from  The  Psychological  Rbvikw,  Vol.  XII.,  No.  5,  Sept.,  1905.] 


THE  DIFFERENCE  BETWEEN  MEN  AND  WOMEN  IN 

THE  RECOGNITION  OF  COLOR  AND  THE 

PERCEPTION  OF  SOUND. 

BY  MABEL  LORENA  NELSON, 
University  of  California. 

(Communicated  by  Professor  Howison.) 

I.  The  Recognition  of  Color. 

In  testing  the  sensitivity  of  the  eye  to  colors,  Dr.  Nichols 
found  that  men  where  more  sensitive  to  red,  ^'■ellow  and  green, 
while  the  women  excelled  in  blue.  He  mixed  a  white  powder 
with  colored  pigments.  A  series  of  mixtures,  varying  from 
white  to  clearly  colored  mixtures,  were  presented  to  the  sub- 
jects (31  men  and  23  women),  who  sorted  them  according  to 
shade  and  hue.  When  once  the  women  recognized  the  color  of 
the  compound,  they  were  more  accurate  in  detecting  the  degree 
of  saturation  of  the  various  mixtures  ;  yet  with  the  exception  of 
blue  the  women  required  more  parts  of  the  pigment  mixed  with 
the  white  before  the  tint  of  the  compound  was  recognized. 

Miss  Thompson,  on  the  other  hand,  finds  that  women  are 
the  more  sensitive  to  colors.  She  tested  20  men  and  20  woman 
with  five  colors,  and  found  that  the  women  could  recognize 
squares  of  colored  paper  (red,  green  and  blue)  at  a  greater  dis- 
tance than  could  the  men.  The  squares  were  pasted  on  cards, 
one  black  and  one  white.  The  tests  were  conducted  in  a  dark 
room,  the  cards  being  illuminated  by  a  Welsbach  burner.  Her 
conclusion  is  that  men's  eyes  are  surely  less  keen  in  the  recog- 

1  Edward  L.  Nichols,  '  On  the  Sensitiveness  of  the  Eye  to  Colors  of  a  Low 
Degree  of  Saturation,'  Am.  four,  of  Science^  Series  3,  Vol.  30  (18S5),  p.  37. 

271 


Onlwfsltjj  of  California 

logical  Labofafof], 


272  MABEL  L.  NELSON. 

nition  of  the  color  of  an  object.      "Yellow  is  the  only  color  for 
which  the  men's  record  is  better  than  the  women's."  ^ 

By  a  different  method  than  either  of  the  two  mentioned 
above,  I  attempted  to  discover  the  difference  between  men  and 
women  in  the  recognition  of  color.  In  the  following  experi- 
ments a  Glan  spectrophotometer  was  used;  the  source  of  light 
was  a  Welsbach  burner  placed  .43  meters  from  the  instrument. 

Before  beginning  my  work,  August,  1903,  I  selected  five 
bands  of  color  in  the  spectrum,  which  appeared  to  me  to  be  char- 
acteristic of  red,  yellow,  green,  blue  and  violet.  The  wave- 
lengths of  the  middle  of  the  five  bands  were  approximately, 
A, 6575,  X5800,  X.  5250,  X4700  and  X4450,  respectively.  The 
five  bands  were  spacially  equal  in  width,  and  measured  about 
one  twentieth  of  the  length  of  the  visible  spectrum.  During 
the  tests  all  the  spectrum  was  cut  off  except  the  band  which 
stood  for  one  of  these  five  colors.  The  subject  then  looked  into 
the  eye-piece  of  the  spectrophotometer,  and  was  asked  to  observe 
and  name  the  color,  while  the  intensity  of  light  was  raised  from 
0°  to  a  maximum,  by  slowly  revolving  the  Nicol  prism  of  the 
apparatus  through  an  angle  of  90°.  The  figures  in  tables  I., 
II.,  and  III.,  represent  the  readings  in  this  angular  scale,  and. 
not  the  absolute  intensity  of  the  light.  The  intensity  of  the 
light  at  any  time  varies  approximately  as  the  sin^«;  a  being  the 
reading  on  the  scale. 

Yet  even  at  0°  there  is  some  illumination  of  the  spectrum 
(due  to  dispersion  of  light  by  the  prism),  so  that  at  0°  every 
subject  was  able  to  see  a  band  of  light,  which  in  general  appeared 
white  or  gray.  A  few  subjects  could  confidently  recognize  the 
color  of  the  band  at  0°.  The  violet  end  of  the  spectrum  is  of 
such  low  intensity  that  a  blue-violet  was  chosen.  The  yellow 
strip  selected  includes  all  the  yellow  in  the  spectrum  with  a 
narrow  band  of  yellow-green  on  one  side,  and  a  narrow  band  of 
orange  on  the  other.  A  strip  narrow  enough  to  have  included 
only  pure  yellow  would  have  been  too  narrow  to  be  used  with 
the  other  colors,  without  being  recognized  by  its  lessened  width, 
and,  on  the  other  hand,  the  width  of  the  other  colors  could  not 

•  Helen  Bradford  Thompson,  Psychological  Norms  in  Men  and  Wometi, 
University  of  Chicago  Press  (1903),  p-  87. 


DIFFERENCES  BETWEEN  MEN  AND    WOMEN.  273 

well  be  reduced  without  making  their  area  so  small  as  to  be 
recognized  with  difficulty  by  untrained  observers. 

Three  separate  hours  were  given  to  the  experiment  by  each 
of  the  40  subjects.  During  the  first  hour  the  subject  was  tested 
with  Holmgren's  worsteds  for  color-blindness.  This  took  from 
30  to  40  minutes.  The  room  was  then  darkened,  and  the 
remainder  of  the  hour  was  spent  in  practice  upon  observation  of 
strips  of  the  spectrum.  The  second  hour  the  subject  rested  his 
eyes  for  20  minutes  in  the  darkened  room  before  looking  into 
the  photometer.  One  determination  was  then  made  for  each  of 
the  5  colors,  but  with  one  eye  only.  The  third  hour  was  a 
repetition  of  the  second,  except  that  the  other  eye  was  used. 

All  conditions  were  kept  as  uniform  as  possible  ;  the  pres- 
sure of  the  gas  was  regulated  by  an  automatic  machanism  and 
constantly  noted ;  and  the  intensity  of  the  color  was  increased 
at  a  constant  rate  of  1°  per  second.  At  the  end  of  every  10 
seconds,  the  subject  looked  away  and  rested  his  eye.  Ten  men 
and  ten  women  used  the  right  eye  first,  and  an  equal  number 
of  men  and  women  used  the  left  first.  The  order  in  which  the 
colors  were  presented  was  varied  ;  a  given  order  was  presented 
to  but  one  man  and  one  woman.  The  subjects  were  not  told 
what  colors  would  be  shown  them,  nor  that  the  same  color  would 
be  seen  for  a  second  time.  They  were  asked  to  look  into  the 
instrument,  to  report  as  soon  as  they  saw  any  color,  and  to  name 
the  color  as  soon  as  they  could  recognize  it. 

There  is  a  disadvantage  in  depending  entirely  on  the  name 
given  to  the  color  seen,  but  this  was  minimized  as  far  as  possible, 
for  any  peculiarity  in  naming  the  colors  was  noted  when  the 
subjects  sorted  the  Holmgren  worsteds  ;  and  when  there  was  any 
doubt  in  my  mind,  or  in  the  mind  of  the  subject,  the  worsteds  were 
brought  out  again  and  correction  was  made  for  any  peculiarity 
in  nomenclature.  At  times  I  could  decide  on  no  threshold  (as 
in  a  case  when  the  subject  saw  no  green  at  all,  but  at  the  maxi- 
mum intensity  called  that  color  yellow).  It  therefore  happens 
that  the  average  and  median  are  at  times  calculated  on  less  than 
20  cases.  I  did  not  assume  that  the  threshold  for  such  subjects, 
as  the  one  just  mentioned,  was  greater  than  90,  for  at  90  the 
strip  was  distinctly  visible  to  him,  and  any  increase  in  intensity 


274 


MABEL  L.  NELSON. 


would  only  serve  to  make  it  more  yellow.  Even  when  green 
was  suggested  to  him,  he  refused  to  accept  it  as  a  proper  name 
for  the  color. 

The  results  of  these  tests,  according  to  one  method  of  com- 
putation, appear  in  Table  I.  Using  the  average  as  the  basis  of 
our  deductions,  it  would  appear  that  the  right  eye  of  men  is 
better  than  the  right  eye  of  women  for  all  colors  but  violet ;   and 

Table  I. 

Threshoi^ds  For  the;  Recognition  of  C01.0R  (in  Angles  of  Nicol's 

Prism). 

Women. 


Right  Eye. 

Left  Eye. 

•6 

i 
0 

"3 

a 

ID 

3 

2 

"3 

1 

d 

V 

3 

5 

■3 

> 

0 

> 

>- 

0 

> 

Average. .  .    . 

II.6 

13.8 

II-3 

25.02 

24-3^ 

8.8 

7-9 

8.0 

28.82 

26.4 

M.  V.  from  Av. 

S.4 

9-5 

5.1 

11. 2 

8.0 

3-7 

5.6 

2.5 

15-3 

9-7 

Median   .    .    . 

7-5 

1 0.0 

1 0.0 

20.02 

20.0 

lO.O 

7.0 

8.0 

24.02 

25-5 

Men. 


Average. .  .    . 
M.  V.  from  Av. 

Median   .    .    . 

8.9 
3-6 
S.o 

6.7 
8.0^ 

8.0^ 

2.0 

lo.o' 

16.9^ 

7-3 

28.43 
25.03 

7.6    13.7 
5-1      8.3 
6.S    1 0.0 

7-3' 
2.4 
7.0' 

17.4' 
10.8 

26.6« 
10.4 

/p.o2 

Table  II. 

Women. 


Right  Eye. 

Left  Eye. 

1 

a 

u 
u 

0 

43 

3 

B 

(U 

> 

■d 

1 

"53 
> 

Green. 

a3 

3 

s 

"o 

> 

Average. .  .    . 

8.4 

5-8 

9-9 

17-5 

22.4 

7-5 

4.8 

7-2 

18.8 

25-1 

M.  V.  from  Av. 

6.4 

3-7 

3-2 

6.6 

5-9 

2.1 

3.8 

2.9 

9.0 

8.8 

Median  .    .    . 

7.0 

4-5 

lO.O 

18.0 

20.0 

7-5 

4.0 

8.0 

18.0 

25-5 

Men. 


Average..  .  . 
M.  V.  from  Av. 
Median  .    .    . 


7-7 

8.2 

9.4' 

/5.02 

27.63 

6.3 

7.0 

12.0 

14-3' 

4.6 

34 

3-2 

7.0 

II.O 

4.6 

3-6 

8.5 

2.5 

7.0 

7.5 

9.02 

14.6^ 

23.03 

5-0 

9.0 

7-5 

14.0^ 

23-3' 

6.8 

^0.53 


1  An  italic  numeral  in  tables  I.,  II.,  and  III.,  indicates  that  it  is  less  than  the 
corresponding  numeral  for  the  other  sex. 

2  19  subjects. 
2 17  subjects. 


DIFFERENCES  BETWEEN  MEN  AND    WOMEN. 


275 


Table  III. 
Women, 


] 

Right  Eye. 

I.eft  Eye. 

•6 

i 

0 

a 
u 

OJ 

u 

0 

> 

•6 

Green. 

6 

3 

s 

0 
> 

Average. .  .    . 

5-1 

.?•«? 

7-0 

12.0 

17.0 

5-9 

.?-^ 

6.4 

14.6 

21. 1 

M.  V.  from  A  v. 

4-1 

34 

3-5 

7.2 

«.3 

34 

3-2 

2.8 

8.1 

9.2 

Median  .    .    . 

3-5 

4.0 

7.0 

13.0 

19.0 

5-0 

3-0 

5-0 

14.0 

23.0 

Men. 


Average. .   .    . 
M.  V.  from  Av. 
Median  .    .    . 

6.5 
5.0 
6.0 

4.6 
3-7 
4.5 

7-5 
3-7 
8.0 

10.4 
3.9 

lO.O 

14-7 

9-1 

17.0 

4-9\ 
4.8 

2-5 

3-6 
3-3 
3.0 

6.8 
3-3 

7-5 

9-5 

4.8 

lO.O 

13.8 

8.7 

/7-5 

that  the  left  eye  of  men  is  better  than  the  left  eye  of  women  for 
red,  green  and  blue;  equal  for  violet,  and  worse  for  yellow. 
The  norm  would  lead  to  the  same  conclusion,  but  if  the  median 
is  used  in  place  of  the  average,  a  somewhat  different  result  is 
obtained.  When  we  consider  the  large  variation,  we  are  prob- 
ably not  justified  in  saying  more  than  that  women  are  in  general 
less  keen  in  the  recognition  of  colors.  Yellow  and  violet  are 
the  only  colors  in  which  they  seem  to  excel,  and  in  these  they 
excel  with  but  one  eye. 

Yellow  was  the  color  most  difficult  to  name  at  a  low  intensity, 
for  the  traces  of  green  and  orange  on  the  edges  of  the  strip 
selected  confused  the  subjects.  Only  a  few  saw  a  uniform 
color.  More  men  than  women  detected  the  presence  of  green 
and  orange.  The  large  threshold  of  both  men  and  women  is 
probably  due  to  the  inability  to  find  an  appropriate  name  for  this 
complex,  rather  than  to  a  low  sensitivity  to  the  color  itself.  The 
larger  threshold  of  the  men  may  possibly  be  due  to  their  greater 
sensitivity  to  the  green  and  orange,  and  consequently  their 
greater  confusion. 

The  women's  failure  to  name  the  colors  correctly  at  a  low 
intensity  cannot  be  due  to  their  ignorance  of  the  proper  name, 
since  at  the  maximum  intensity  they  named  the  colors  as  accu- 
rately as  did  the  men.  Table  IV.  gives  the  different  names 
applied  to  the  colors  as  they  appeared  at  the  maximum  intensity, 
with  the  number  of  men  and  women  using  each  name.  The 
parenthesis  indicates  that  the  subjects  added  those  words  after 


276 


MABEL  L.  NELSON. 


being  pressed  for  a  closer  description,  and  in  many  cases  only- 
after  other  colors  had  been  suggested  to  them.  In  some  cases 
the  subjects  gave  two  and  even  three  names  to  the  strip  of  color 
shown  them.  As  the  strips  were  practically  uniform,  with  the 
one  exception  of  3'ellow,  it  is  probable  that  the  knowledge  that  a 


Table  IV. 

Names  Given  to  the  Standard  Colors. 

Red. 


Red 

Red  (towards  orange) 
Red  (towards  purple) 

Orange-red 

Red-orange 


Right  Eye. . 


Men. 


14 

4 


12 

4 
2 

I 
I 


Left  Eye 


17 

I 
2 


II 

3 
2 

4 


Yellow. 


Red,  yellow  and  green  . 
Orange-red  and  yellow 
Red  and  orange  .    .    .    . 

Orange 

Orange-yellow  .  .  .  . 
Yellow 


Green, 


Green 

Green  (towards  yellow)  . 

Yellow-green 

Yellow  and  green  .... 
Yellow,  green  and  blue  . 
Orange  and  yellow-green 

Yellow 

Green- yellow 


8 
3 

7 

5 
4 
6 

3 

6 

10 

I 

2 

I 

2 

I 

I 

Blue. 


Blue 

Violet-blue 

Green-blue 

Violet,  green  and  blue 

Blue-green 

Blue-violet 

Blue  and  violet    .    .    . 


786 
4  5 

6  3  5 

633 
I 

III 


Violet. 


Violet 

Violet  (towards  blue) 
Violet  (towards  red) 

Blue-violet 

Violet-blue 

Blue 

Blue  (towards  green) 


12 

14 

14 

6 

2 

6 

2 

I 
2 

I 

DIFFERENCES  BETWEEN  MEN  AND    WOMEN. 


377 


spectrum  was  being  used  helped  to  suggest  the  neighboring 
colors,  though  no  doubt  some  subjects  did  actually  discern  a 
difference  in  the  two  edges  of  the  band. 

At  the  close  of  the  tests,  10  men  and  an  equal  number  of 
women  were  shown  the  whole  spectrum,  and  asked  to  select  the 
5  portions  which  they  called  the  best  and  purest  bands  of  red, 
yellow,  green,  blue  and  violet.  The  results  are  given  in 
Table  V.     The  numbers  represent  the  centers  of  the  narrow 

Table  V. 

Readings  in  Case  of  Free  Selection  of  Colors. 

Women. 


Right  Eye. 

Left  Eye. 

i- 

_j 

i 

_J 

■o 

0 

"O 

0 

s 

"3 
!> 

11 

"3 

0 

s 

0 

> 

Average    .... 

8.42 

10.57 

12.99 

15.96 

17-93 

8.53 

10.84 

13.13 

16.18   17.92 

M.  V.  from  Av  . 

•17 

.19 

•45 

•27 

.28 

.18 

•31 

.34 

.25      .24 

Median     .... 

8.45 

10.48 

12.75 

15.82 

18.01 

8.52 

10.83 

13.25 

16.20   17.92 

Men. 


Average    .... 

M.  V.  from  Av  . 

Median     .... 

Readings  actu- 
ally used  for 
standard  colors 


8.47 

.09 

8.48 


8.50 


10.83 

.21 

10.80 


10.50 


12.57 

•43 

12.88 


12.50 


16.13 

.60 

15.94 

16.00 


18.23 

.40 

18.24 

18.00 


'.52 
.14 
'.51 


10.74 

.38 

10.75 


12.89 

.41 

12.90 


15.99 

.25 

16.03 


18.34 

.55 

18.30 


band  chosen,  the  visible  spectrum  running  from  about  7  to  22 
—  beyond  23  for  some  of  the  subjects.  The  standard  colors 
used  in  the  preceding  tests  are  represented  by  the  numbers  8.5, 
10.5,  12.5,  16  and  18.  The  colors  selected  by  the  subjects  are 
close  to  those  used  in  the  tests.  The  wave-lengths  are  approxi- 
mately the  same  except  for  yellow  and  green.  A  5700  was 
chosen  for  yellow  by  the  left  eye  of  women,  and  by  the  right 
eye  of  men  ;  and  A  5150  was  chosen  for  green  by  the  left  eye 
of  women.  This  is  consistent  with  the  fact  that  so  large  a  num- 
ber called  the  standard  green  a  yellow-green  (see  Table  IV.). 
From  the  names  given  to  the  standard  violet  we  might  expect 
the  subjects  to  choose  a  violet  farther  away  from  the  blue.  It 
is  true  that  the  men  did,  yet  the  difference  between  18  and  18.34 
is  not  perceptible.     In  endeavoring  to  choose  the  colors  on  dif- 


zyS  MABEL  L.  NELSON. 

ferent  days,  I  find  in  my  own  case  that  the  variation  from  the 
average  is  between  i  per  cent,  and  1.5  per  cent,  for  red,  yellow, 
green  and  violet,  and  a  little  over  2  per  cent,  for  blue,  being 
but  little  less  than  the  variation  from  the  average  of  the  10 
women. 

Instead  of  waiting  until  the  subject  could  name  the  color 
with  certainty,  we  might  take,  as  the  more  probable  threshold 
of  recognition,  the  reading  where  the  color  was  first  correctly 
named,  even  though  it  was  named  with  doubt  and  reservation, 
and  also  the  reading  where  the  subjects  gave  a  name  so  near 
the  standard  as  to  make  it  probable  that  they  recognized  the 
standard  color,  but  had  not  secured  the  most  appropriate  name. 
For  comparison  I  have  calculated  this  probable  threshold  and 
in  so  doing  I  have  allowed  myself  some  freedom.  I  have  not 
taken  the  lowest  reading  when  my  knowledge  of  the  subject 
and  the  evidence  of  later  reports  made  it  certain  that  the  first 
correct  report  was  merely  a  lucky  guess. 

Comparing  these  results,  given  in  Table  II.,  with  those  given 
in  Table  I.,  we  see  that  woman's  record  with  the  right  eye  is 
here  lower  than  man's  for  yellow  as  well  as  for  violet ;  her 
record  with  the  left  eye  is  still  lower  for  yellow,  and  in  addition 
is  probably  lower  for  green.  These  results,  differing  as  they 
do  from  those  obtained  from  Table  I.,  may  simply  mean  that 
the  men  were  more  cautious,  that  they  did  not  venture  a  name 
until  they  were  fairly  sure  it  would  fit ;  while  the  women  would 
speak  as  soon  as  they  discovered  the  region  to  which  the  color 
belonged,  afterwards  locating  it  more  exactly. 

Going  over  the  original  data  for  a  third  time,  I  calculated  the 
thresholds  in  still  another  way.  The  threshold  is  now  taken  to 
be  the  reading  where  some  closely  kindred  color  or  some  com- 
ponent of  the  color,  as  it  appeared  to  the  subject  at  the  maximum 
intensity,  was  named.  For  example,  if  at  the  maximum  a  color 
appeared  green-blue  to  a  certain  subject,  then  we  may  assume 
that  at  the  first  mention  of  either  blue  or  green,  the  color  was 
really  perceived  by  that  subject.  Table  III.  shows  the  thres- 
holds calculated  in  this  way.  Orange  was  accepted  as  a  cor- 
rect answer  for  either  red  or  yellow ;  if  the  green  seemed  a 
yellow-green,   then  either  yellow  or  green  was  accepted  for 


DIFFERENCES  BETWEEN  MEN  AND    WOMEN.  279 

green.  Ample  allowance  is  thus  made  for  individual  dif- 
ferences of  nomenclature  ;  and  we  have  a  threshold  of  recog- 
nition of  something,  which  is  a  close  approach  to  the  standard, 
if  it  is  not  the  standard  itself.  Woman's  right  eye  is  superior  to 
man's  right  in  this  kind  of  recognition  when  the  standards  are 
red,  yellow  and  green :  her  left  is  superior  to  man's  left  when 
the  standards  are  yellow  and  green.  The  superiority  of  men 
in  blue  and  violet  is,  on  the  whole,  more  marked  than  is  the 
superiority  of  women  in  yellow  and  green. 

When  we  compare  Tables  I.,  II.  and  III.,  we  find  that  in 
spite  of  some  discrepancies,  there  is  a  certain  uniformity.  In 
every  instance  the  men  have  a  lower  threshold  for  blue.  For 
the  left  eye  they  have  a  practically  equal  or  lower  threshold  for 
violet ;  for  the  right  eye  a  greater  for  violet,  except  when  blue 
or  violet-blue  is  accepted  as  a  correct  answer.  It  seems  certain 
that  the  men  could  distinguish  blue  and  the  blue  factor  in  the 
violet  at  a  lower  intensity  than  could  the  women.  In  the  blue 
of  the  3  tables  there  is  at  no  time  more  than  4  men  who  fail  to 
excel  the  average  woman  with  the  left  eye ;  and  never  more 
than  7  men  who  fail  to  excel  the  right  eye  of  the  average 
woman.  With  the  exception  of  the  right  eye  in  Table  I.,  and 
possibly  the  left  in  Table  III.,  women  have  the  lower  threshold 
for  yellow ;  yet  there  are  always  from  6  to  10  women  who  fail 
to  excel  the  average  man.  Women  excelled  in  red  when 
orange  was  accepted  as  a  correct  answer.  The  instances  when 
they  excelled  in  green  are  those  in  which  yellow  and  green- 
yellow  are  accepted  as  correct  answers. 

Taking  into  account  all  3  methods  of  calculating  the  thres- 
holds, the  general  conclusion  would  be,  that  men  are  clearly 
superior  in  the  recognition  of  blue ;  and  women  are  possibly 
superior  in  the  recognition  of  yellow.  These  results  do  not 
agree  at  all  with  those  of  Miss  Thompson,  who  found  that  men 
excelled  in  yellow  alone.  The  difference  between  my  results 
and  those  of  Miss  Thompson  may  be  due  to  the  fact  that  14  out 
of  the  25  men  she  tested  fell  into  the  two  classes,  which  she 
designates  as  '  color-blind  '  and  '  poor  in  color  discrimination  ' ; 
while  none  of  her  women  were  '  color-blind,'  and  only  4  were 
'poor.'^     No    color-blind    person    is    included    in    my    report, 

^Psychological Norms,  page  88. 


28o  ,         MABEL  L.  NELSON. 

although  5  men  and  3  women  might  be  called  poor  in  color  dis- 
crimination. Their  mistakes  consisted  in  mixing  some  of  the 
blues  and  greens,  and  in  failing  to  detect  anything  but  a  pale 
tint  of  red  in  our  laboratory  sample  of  Holmgren's  purple.  In 
naming  the  spectrum  colors,  however,  these  subjects  appear  to 
be  as  good  as  the  average  subject  tested. 

Miss  Thompson  finds  that  the  left  eye  of  woman  excels  her 
right  in  all  but  3^ellow.  In  my  tables  her  left  eye  seems  superior 
in  yellow  and  green ;  yet  when  the  number  of  individuals  are 
counted  up,  there  are  but  11  whose  left  eye  excels  the  right  in 
yellow,  and  14  in  green  ;  for  the  other  three  colors  there  is  no 
difference  between  the  two  eyes.  Miss  Thompson  finds  man's 
left  eye  has  a  better  record  in  yellow  alone.  I  find  that  in 
yellow  there  are  12  men  who  have  a  better  right  eye,  against  6 
who  have  a  better  left ;  yellow  is  the  only  color  in  which  his 
right  eye  excels.  In  red  and  green  I  find  no  difference,  but  in 
blue  and  violet  the  left  eye  excels  ;  in  blue  5  men  have  a  better 
right  eye,  8  a  better  left ;  in  violet  9  have  a  better  left,  3  a  better 
right. 

Each  of  the  subjects  was  asked  which  eye  he  preferred  to  use. 
Most  of  them  had  no  preference.  Of  the  20  women,  5  prefered 
to  use  the  left  eye.  Each  gave,  independently,  the  same  reason  ; 
in  looking  into  the  instrument  with  one  eye  they  alway  kept  the 
other  closed,  and  could  with  less  effort  keep  the  right  eye  closed. 
One,  a  left-handed  woman,  prefered  to  use  her  right  for  the 
same  reason,  that  is,  she  found  it  easier  to  keep  her  left  eye 
closed.  Only  2  men  expressed  a  preference  ;  both  preferred  to 
use  the  right,  they  were  in  the  habit  of  looking  into  instruments 
and  were  accustomed  to  using  the  right  eye.  In  the  results  of 
these  subjects  I  can  find  no  consistent  advantage  of  the  preferred 
eye  over  the  other. 

II.  The  Perception  of  Sound. 
The  following  experiments  were  undertaken  with  the  object 
of  finding  any  difference  that  may  exist  between  men  and  women 
with  regard  to  the  absolute  threshold  for  hearing.  The  individ- 
uals tested,  20  men  and  20  women,  were  all  students  in  the 
University  of  California. 


DIFFERENCES  BETWEEN  MEN  AND    WOMEN.  281 

An  electric  tuning-fork  of  100  double  vibrations  was  used  in 
these  tests.  The  noise  which  attends  the  sparking  of  the  elec- 
tric contact  was  avoided  by  connecting  up  the  fork  in  series 
with  a  second  fork  of  100  vibrations  in  a  distant  room  ;  this 
second  fork  interrupted  the  current  in  the  first  and  permitted  its 
use  with  continuous  closed  contact,  and  thus  a  noiseless  pure 
tone  was  obtained.  By  means  of  a  galvanometer  and  resistance 
the  current  was  kept  constant ;  and  by  the  constant  use  of  com- 
mutators any  permanent  alteration  in  the  magnet  of  the  tuning- 
fork  was  prevented.  The  subject  sat  in  an  ordinary  research 
room,  behind  a  screen  in  which  was  an  aperture  large  enough 
to  receive  the  ear.  During  the  tests  the  subject  sat  with  his 
head  pressed  against  the  screen,  his  ear  within  the  aperture. 
The  intensity  of  the  sound  was  altered  by  varying  the  distance 
of  the  tuning-fork  from  the  screen. 

For  each  of  the  subjects,  a  first  rough  estimate  of  the  greatest 
distance  at  which  the  sound  could  be  heard  was  made.  Then 
beginning  somewhat  within  this  distance,  tests  were  made  at 
intervals  of  2.5  centimeters.  At  each  interval  a  group  of  10 
tests  were  made,  5  with  the  tuning-fork  going  and  5  with  it 
stopped.  The  order  in  which  the  two  kinds  of  tests  were  taken 
was  constantly  varied.  All  the  series  of  groups  were  run  from 
above  to  below  the  threshold.  The  subject  was  given  a  warn- 
ing ;  he  then  placed  his  ear  at  the  aperture  and  reported  whether 
he  heard,  or  did  not  hear  the  sound.  When  the  subject  was 
doubtful  the  test  was  repeated.  Between  the  groups  the  subject 
relaxed  his  position  and  rested.  The  greatest  distance  at  which 
80  per  cent,  of  the  answers  were  correct  was  recorded  as  the 
threshold,  though  groups  of  tests  were  also  made  beyond  this 
point  to  make  sure  that  the  falling  off  of  correct  answers  was 
not  accidental  nor  momentary.  The  thresholds  are  recorded 
in  Table  I.  ;  the  figures  represent  the  number  of  centimeters 
from  the  screen.  The  average  and  also  the  median  of  the 
20  subjects  are  given.  One  man's  threshold  was  more  than 
twice  as  great  as  that  of  any  other  one  of  the  40  subjects.  I 
have  therefore  also  given  the  average  of  19  men,  excluding 
this  one.  Among  the  women  there  was  none  that  seemed  ex- 
ceptional. 


28 2  MABEL  L.  NELSON. 

Table  I. 

Threshold  for  Hearing  in  Centimeters.    Series  I. 

20  Women.  20  Men. 

Right  ear.        Left  ear.  Right  ear.        Left  ear. 

Average 44.75  38.00  70.25  53.50 

Median 42-50  35-oo  53.75  4S.75 

19  Men. 
Average  .    .    .    54.50  4S.50 

Variation  from  the  Average. 

20  Women.  20  Men. 

Right  ear.  Left  ear.  Right  ear.  Left  ear. 

9.8  9.1  21.0  12.8 

19  Men. 
8.7  7.7 

The  average  women  of  the  20  could  hear  17  per  cent,  far- 
ther with  the  right  ear  than  with  the  left.  The  average  man  of 
the  20  could  hear  31  per  cent,  farther  with  the  right  than  with 
his  left.  The  average  man  of  the  19  could  hear  12  per  cent, 
farther  with  his  right  than  with  his  left. 

The  average  man  of  the  20  could  hear  19  per  cent,  farther 
with  his  left  ear  than  the  average  woman  could  hear  with  her 
right  ear.  The  average  man  of  the  19  could  hear  8  per  cent, 
farther  with  the  left  ear  than  the  average  of  the  20  women  could 
hear  with  her  right. 

The  results  show  that  both  the  women  and  the  men  could 
hear  farther  with  the  right  ear  than  with  the  left.  The  men 
hear  much  better  than  the  women.  There  was  but  one  woman 
who  excelled  the  average  man ;  and,  on  the  other  hand,  only  3 
men  fall  below  the  average  women.  Eight  women  fall  below 
the  lowest  man.  The  men  not  only  could  hear  further  than  the 
women,  but  the  poorer  ear  of  the  men  was  much  keener  than 
the  better  ear  of  the  women. 

A  second  set  of  experiments  was  then  undertaken,  this  time 
with  a  tuning-fork  of  500  double  vibrations.  The  same  subjects, 
with  the  exception  of  2  men  and  2  women  were  used  in  these 
tests.  More  precautions  against  external  noises  were  taken. 
The  subject  sat  in  a  silent  room,  from  which  all  noises  were  ex- 
cluded by  specially  constructed  walls  and  doors.  One  end  of 
a  lead  pipe  has  its   termination   in   this  silent  room,  while  the 


DIFFERENCES  BETWEEN  MEN  AND    WOMEN.  283 

Other  end  terminates  in  a  research  room  in  another  wing  of  the 
laboratory.  The  screen  used  in  the  first  series  of  tests  was  set 
up  in  the  silent  room,  1.675  meters  from  the  end  of  the  lead 
pipe.  The  tuning-fork  of  500  vibrations  was  set  at  varying 
distances  from  the  other  end  of  the  pipe  in  the  distant  room 
where  the  experimenter  was.  The  appearance  of  a  light  in  the 
dark  room  served  to  warn  the  subject,  who  then,  as  before, 
placed  his  ear  at  the  aperture  in  the  screen.  Here  and  in  the 
earlier  series  of  experiments,  half  of  the  men  and  half  of  the 
women  used  the  right  ear  first,  the  other  half  used  the  left  first. 
The  subject  communicated  his  answers  by  means  of  a  telegraphic 
key.  After  a  first  rough  estimate  of  the  threshold  was  made, 
10  tests  were  made  at  regular  intervals  of  i  centimeter.  The 
method  used  was  the  same  as  the  first  group  of  tests.  The  fig- 
ures in  Table  II.  are  in  centimeters,  and  represent  the  distance 
of  the  tuning-fork  from  the  end  of  the  tube. 

Table  II. 
Thr:eshoi<d  for  Hearing  in  Centimeters.    Series  II. 
18  Women,  18  Men. 

Right  Ear.     Left  Ear.  Right  Ear.      Left  Ear. 

Average 6.88  5.66  8.61  7.77 

Median 7.00  5.50  8.50  6.00 

Variation  from  the  Average. 
20  Women.  20  Men. 

Right  Ear.         Left  Ear.  Right  Ear.  Left  Ear. 

3.50  3.16  5.00  4.80 

The  average  woman  could  hear  21  per  cent,  farther  with 
her  right  ear  than  with  her  left  ear.  The  average  man  could 
hear  10  per  cent,  farther  with  his  right  than  with  his  left  ear. 

The  average  man  could  hear  1 1  per  cent,  farther  with  his 
left  ear  than  the  average  woman  could  hear  with  her  right  ear. 

The  results  are  as  before :  the  men  hear  farther  than  the 
women ;  the  right  ear  of  both  men  and  women  is  keener  than 
the  left.  The  changed  conditions  and  the  difference  in  the  note 
has  not  changed  the  general  result,  though  it  affected  the  rela- 
tive positions  of  individuals  within  the  groups  of  subjects.  The 
two  men,  whose  records  were  the  highest  in  the  tests  with  the 
tuning-fork  of  100  vibrations,  fell  below  the  average  of  the  men 


284  MABEL  L.  NELSON. 

when  the  fork  of  500  vibrations  was  used.  The  two  women 
who  stood  highest  in  the  first  series  of  tests  also  stood  highest 
in  the  second  series  ;  but  in  general  it  is  not  true  that  the  women 
who  heard  farthest  in  the  first  series,  also  heard  farthest  in 
the  second  series.  Fully  50  per  cent,  of  the  men  whose  records 
were  higher  than  the  median  in  the  first  series,  fell  below  the 
median  in  the  second  series  ;  the  same  is  true  of  the  women, 
although  the  women  do  not  make  such  a  decided  change. 
They  change  from  a  short  distance  on  one  side  of  the  median 
to  a  short  distance  on  the  other.  The  superiority  of  the  men  is 
not  so  marked.  With  the  left  ear,  7  women  excel  the  average 
man;  with  the  right  ear,  4  women  excel  the  average  man. 
Eight  men  fall  below  the  average  woman  with  both  the  right 
and  left  ear. 

The  superiority  of  the  right  ear  over  the  left  is  as  marked  in 
this  second  series  as  it  was  in  the  first.  Not  only  was  the  right 
ear  of  the  average  man  and  average  woman  better  than  the  left, 
but  the  right  ear  of  almost  every  individual  subject  was  either 
better  than,  or  equal  to,  the  left  (see  Table  III.).     Of  the  40 

Series  i. 

Number  of  women  with  a  better  right  ear 16 

Number  of  men  with  a  better  right  ear 14 

Number  of  women  with  a  better  left  ear i 

Number  of  men  with  a  better  left  ear 2 

Number  of  women  with  the  right  and  left  ear  equal 3 

Number  of  men  with  the  right  and  left  ear  equal 4 

Series  ii. 

Number  of  women  with  a  better  right  ear 12 

Number  of  men  with  a  better  right  ear 14 

Number  of  women  with  a  better  left  ear 3 

Number  of  men  with  a  better  left  ear 3 

Number  of  women  with  the  right  and  left  ear  equal 3 

Number  of  men  with  the  right  and  left  ear  equal i 

subjects,  but  one  man  was  found  whose  left  ear  was  better  than 
his  right  in  both  series.  Of  the  remaining  5  subjects  whose  left 
proved  better  than  the  right  in  second  series,  the  right  and  left 
of  two  had  been  equal,  the  right  of  3  had  been  slightly  better 
than  the  left  in  the  first  series. 

None  of  the  40  subjects  knew  of  any  defect  in  their  hearing. 
They  were  asked  if  they  knew  of  any  difference  between  the 


DIFFERENCES  BETWEEN  MEN  AND   WOMEN.  2S5 

right  and  the  left  ear.  Seven  (2  woman  and  5  men)  thought 
the  right  was  better ;  5  (3  women  and  2  men)  thought  the  left 
better.  None  of  these  gave,  or  pretended  to  give,  any  good 
reason  for  their  opinion  ;  and  in  every  case  their  opinion,  when 
they  thought  better  of  the  left,  was  not  in  accord  with  the  results 
of  the  tests.  The  one  man  whose  left  ear  proved  to  be  better, 
knew  of  no  difference. 

The  results  indicating  more  acute  hearing  in  the  men  can- 
not be  due  to  a  greater  recklessness  in  answering.  If  this  were 
true,  we  would  expect  the  men  to  make  more  errors  than  the 
women  when  the  fork  was  silent.  On  the  whole  they  made 
fewer  such  errors.  Many  subjects  made  no  errors  of  this  kind. 
In  the  first  series,  9  men  made  a  total  number  of  46  errors,  20 
with  the  left  ear  and  26  with  the  right ;  9  women  made  42 
errors,  9  with  the  left  and  33  with  the  right.  In  the  second 
series  the  men  were  more  cautious;  6  men  made  a  total  of  21 
errors,  9  with  the  right,  12  with  the  left;  13  women  made  68 
errors,  29  with  the  right,  and  39  with  the  left. 

Many  in  this  second  series  did  not  use  the  signal  '  doubtful ' 
at  all.  The  number  of  such  answers  is  given  in  Table  IV.  In 
this  second  series  the  left  ear  of  both  men  and  women  was  not 
only  less  acute,  but  more  doubt  was  expressed  and  more  errors 
made  when  it  was  used ;  the  variation  from  the  average  is  also 
slightly  greater. 

Table  IV. 

Series  II. 
Right  ear,  fork  sounding. 
45  '  doubtful '  answers  were  made  by  14  women. 
95  "  "  "         "      "    16    men. 

Right  ear,  fork  silent. 
6  '  doubtful '  answers  were  made  by  4  women. 
2  "  "  "        "       "  2    men. 

Left  ear,  fork  sounding. 
53  '  doubtful '  answers  were  made  by  13  women. 
116  "  "  "        "       "    16    men. 

Left  ear,  fork  silent. 
No  '  doubtful '  answers  made. 

Fechner  ^  found  the  left  ear  to  be  better  than  the  right.     His 

'  In  Poggendorfs  Aiinalen  der  Physik  und  chemie,  vierte  Reihe,  Band  iii. 
S.  500. 


386  MABEL  L.  NELSON. 

method  was  to  place  a  watch  directly  before  the  subject,  who 
after  closing  with  the  forefinger  first  one  ear  then  the  other, 
stated  in  which  ear  the  watch  seemed  louder.  Such  a  method 
records  only  the  subject's  opinion.  I  found  that  results  obtained 
by  a  test  similar  to  Fechner's  were  not  in  accord  with  the  results 
obtained  by  the  tests  with  the  tuning-fork.  The  subjects  were 
the  same  i8  men  and  i8  women  used  in  the  second  series  of 
tests  with  the  tuning-fork.  A  watch  was  held  in  front  of  the 
subject,  who,  after  turning  the  head  slowly  from  side  to  side, 
stated  in  which  ear  the  watch  seemed  louder.  Eight  (4  men 
and  4  women)  said  the  watch  seemed  louder  in  the  left  ear. 
The  former  tests  seemed  to  show  that  the  left  ear  of  but  one  man 
was  better ;  the  right  ear  of  the  remaining  7  had  been  shown  to 
be  better.  Five  (i  man  and  4  women)  said  the  watch  seemed 
louder  in  the  right ;  the  remainder  of  the  subjects  could  tell  of 
no  difference.  Again,  I  brought  the  watch  from  a  point  beyond 
to  a  point  within  the  range  of  hearing,  and  asked  the  subjects 
with  which  ear  they  first  heard  the  sound.  The  8  subjects 
mentioned  in  the  first  test  with  the  watch,  answered  that  they 
heard  it  first  with  the  left  ear;  and  the  same  5,  who  before 
seemed  to  hear  it  louder  with  the  right,  now  said  they  heard  it 
first  with  the  right ;  the  remainder  of  the  subjects  could  tell  no 
difference.  There  thus  seems  to  be  a  slight  tendency  to  think 
better  of  the  left  ear,  even  when  that  ear  is  the  poorer.  It  is  of 
course  possible  that  if  a  tuning-fork  had  been  used  instead  of  a 
watch  a  different  result  would  have  been  obtained.^ 

2The  MS.  of  this  article  was  received  March.  11,  1905. — Ed. 


Onlwrsltj  of  California 

Psyottoiogjcal  laboratonf. 


REPRINTED  FROM 

VOL  XII.  No.  5.  September,  1905. 

THE 

Psychological    Review 

EDITED  BY 
J.  MARK  BALDWIN  HOWARD  C.  WARREN 

Johns  Hopkins  University  ^^^  Princeton  University 

CHARLES  H.  JUDD,  Yale  University  [Editor  of  the  Monograph  Series). 

WITH  THE  CO-OPERATION  FOR  THIS  SECTION  OF 

A.  C.  ARMSTRONG,  Wesleyan  University  ;  ALFRED  BINET,  Ecole  des  Hautes- 
feTUDES,  Paris;  W.  L.  BRYAN,  Indiana  University;  WILLIAM  CALDWELL,  Mc- 
GiLL  University;  MARY  W.  CALKINS,  Wellesley  College;  JOHN  DEWEY, 
Columbia  University  ;  J.  R.  ANGELL,  University  of  Chicago  ;  C.  LADD  FRANKLIN, 
Baltimore;  H.  N.  GARDINER,  Smith  College;  G.  H.  HOWISON,  University  of 
California  ;  P.  JANET,  College  de  France  ;  JOSEPH  JASTROW,  University  of  Wis- 
consin; ADOLF  MEYER,  N.  Y.  Pathol.  Institute;  C.  LLOYD  MORGAN,  University 
College,  Bristol;  HUGO  MONSTERBERG,  Harvard  University;  E.  A.  PACE, 
Catholic  University,  Washington;  G.  T.  W.  PATRICK,  University  of  Iowa;  CARL 
STUMPF,  University,  Berlin;  R.  W.  WENLEY,  University  of  Michigan. 


^V% 


EXTENSITY  AND    PITCH 


BY  DR.  KNIGHT  DUNLAP, 
University  of  California. 


THE  MACMILLAN  COMPANY, 

41    NORTH   QUEEN  ST.,   LANCASTER,    PA. 

66    FIFTH    AVENUE,    NEW   YORK. 

Agent:  G.   E.  STECHERT,  London  (2  Gtar  Yard,  Carey  St.    W.  C); 

Leipzig  (Hospital  St„  10;  Paris   (76  rue  de  Renaes). 


Psyatioiogieai  bl3nfS(;^n 


[Reprinted  from  The  Psychological  Review,  Vol.  XII.,  No.  5,  Sept.,  1905.] 


EXTENSITY  AND  PITCH. 

BY  DR.  KNIGHT  DUNLAP, 
University  of  California. 

Psychologists  in  general  agree  that  '  sensation '  has  the  four 
characters  of  quality,  intensity,  duration  (or  protensity),  and 
feeling-tone.  To  these  some  would  add  volume  (or  extensity), 
and  others  would  add  vividness.  There  seems  to  be  no  reason 
why  the  list  should  not  be  somewhat  further  extended  by  add- 
ing local  significance,  which  may  with  advantage  be  distin- 
guished from  quality ;  and  meaning,  or  symbolic  value,  which 
is  at  least  as  important  as  an}^  of  the  other  characters.  Even 
with  these  additions  there  is  question  whether  the  list  is  com- 
plete, but  it  is  sufficiently  so  for  present  purposes. 

These  characters  of  simple  sense  objects  are  not  parallel  in 
their  functions,  but  differ  in  their  relation  to  the  existence  of 
these  sense  objects,  and  in  their  modes  of  variation.  The  first 
three  which  we  have  named  seem  to  be  essential ;  we  can  not 
conceive  of  the  existence  of  a  '  sensation  'which  has  no  duration, 
or  which  has  no  intensity,  or  which  has  no  quality;  i.  e.,  which 
is  no  particular  kind  of  'sensation.'  Whether  the  same  holds 
true  for  extensity  is  perhaps  less  certain,  but  there  is  strong 
evidence  that  way,  as  we  shall  see  later.  Vividness,  feeling 
tone,  local  significance,  and  meaning,  seem  to  be  less  essential. 
There  conceivably  may  be  sense  objects  present  to  conscious- 
ness which  yet  are  of  zero  vividness  ;  that  is,  they  are  either  in 
the  realm  of  so-called  subconsciousness,  or  else  they  are  ne- 
glected in  their  immediate  nature,  and  their  meaning  alone  taken 
into  account.  Local  significance,  again,  may  possibly  be  lack- 
ing ;  olfactory  objects,  in  particular,  never  seem  to  have  in 
themselves  any  local  signs,  although  of  course  they  are  local- 
ized by  the  help  of  tactual  and  muscular  experiences  ;  some- 
thing of  the  same  kind  seems  to  be  true  of  auditory  sensations 
also.     It  may  be  that  local  signs  exist  only  in  touch  and  sight ; 

287 

ilDlYSfsitji  of  Galiforola 

PsyeliQiogioal  Laboratofy. 


2S8  DR.  KNIGHl  DUN  LAP. 

or  on  the  other  hand  it  may  be  that  there  is  a  system  of  local 
signs  present  in  hearing  which  is  represented  by  the  system  of 
pitches  ;  but  at  least  we  can  conceive  of  '  sensations '  which 
should  be  entirely  devoid  of  this  character.  Suppose,  for  in- 
stance, two  nerve  endings  which  should  when  stimulated  produce 
sensual  processes  corresponding  to  the  same  sensuous  quality ; 
there  might  be  in  these  processes  nothing  which  would  enable 
us  to  distinguish  one  from  the  other,  and  yet  both  would  be  real. 

Sense  objects  may  be  neutral  in  feeling-tone,  which  is 
equivalent  to  their  having  no  feeling  tone.  Some  psychologists 
insist  on  calling  neutrality  a  definite  feeling-tone,  thereby  mak- 
ing feeling-tone  an  essential  character ;  but  this  seems  an  un- 
called for  complication,  since  feeling-tone  signifies  the  character 
by  which  states  of  consciousness  differ  as  regards  pleasantness 
(or  unpleasantness,  whichever  you  chose)  and  when  this  factor 
is  reduced  to  zero  there  is  no  better  excuse  for  saying  that  it 
still  exists  than  there  is  for  saying  that  zero  intensity  and  zero 
duration  are  still  existent  intensity  and  duration. 

Meaning,  likewise,  is  not  necessarily  present.  A  sense  ob- 
ject may  conceivably  be  taken  for  just  what  it  is,  without  refer- 
ence to  anything  else.  Of  course,  the  more  experience  we 
have,  the  more  nearly  impossible  this  becomes  ;  but  even  so  we 
may  hold  that  the  absence  of  meaning  does  not  imply  the  non- 
existence of  *  sensation.' 

These  various  characters  of  simple  sense  objects  show  also 
diverse  types  of  behavior  in  the  analysis  of  psychical  com- 
pounds. The  mere  quality  of  a  compound  involves  nothing 
which  is  not  in  the  qualities  of  its  components.  So  the  intensity 
and  duration  are  direct  functions  of  the  intensities  and  durations 
of  its  elements.  Or,  if  the  more  accurate  form  of  statement  is 
preferred,  we  may  say  that  the  qualities,  intensities,  and  dura- 
tions, of  the  elements  into  which  the  complex  state  is  analyzed 
will  include  all  qualities,  intensities,  and  durations  found  in  the 
complex,  and  no  other ;  there  is  neither  surplusage  nor  deficit 
resulting  from  the  analysis.  The  complex  as  a  whole  has  no 
quality  which  cannot  be  reduced  to  the  qualities  of  the  elements  ; 
no  intensity  which  cannot  be  reduced  to  a  summation  of  ele- 
mentary intensities  ;  and  no  duration  which  is  different  from  the 
duration  of  a  definite  number  of  its  elements. 


EXTENSITY  AND  PITCH.  289 

Extensity  falls  in  with  duration.  But  in  both  these  charac- 
ters we  must  be  prepared  for  an  apparent  surplusage  resulting 
from  analysis,  which  apparent  surplusage  is  due  to  the  phenom- 
ena of  superposition;  /.  d*.,  simultaneity  in  time  or  collocation 
in  space.  When  we  take  these  factors  into  account  the  appa- 
rent post-analytical  redundancy  disappears. 

With  regard  to  the  other  characters  of  elementary  sense  ob- 
jects, this  simple  analytic  relation  does  not  hold.  There  are 
factors  in  the  feeling-tone  of  a  complex  that  are  not  assignable 
to  any  of  the  sensuous  elements  into  which  the  complex  maybe 
resolved,  but  which  seem  to  belong  to  the  complex  as  such,  or 
perhaps  to  intellectual  elements.  The  meaning  of  a  complex 
is  far  different  from  the  total  meanings  of  its  elements.  Vivid- 
ness is  scarce  amenable  to  analysis  at  all,  for  to  a  certain  extent 
the  vividness  of  the  complex  as  a  whole  is  inversely  proportional 
to  the  vividness  of  its  elements.  Local  significance  may  be- 
come entirely  lost  in  a  complex,  especially  when  the  complex 
involves  the  cooperation  of  two  or  more  senses,  and  it  appears 
in  these  cases  only  by  the  analysis  of  the  complex  into  its 
elements. 

With  regard  to  their  analytic  behaviour  therefore,  as  well  as 
their  essentiality,  the  feeling-tone,  meaning,  vividness,  and 
local  significance  characters  differ  radically  from  quality,  inten- 
sity, duration,  and  extensity. 

There  is  however  one  way  in  which  quality  differs  funda- 
mentally from  intensity,  duration,  and  extensity,  and  that  is  in 
its  method  of  variation.  The  variations  in  these  last  three  are 
continuous  from  zero  to  the  highest  possible  value,  without  any 
points  of  special  value,  /.  e.,  determining  points,  in  the  contin- 
uum ;  while  the  variations  of  quality  pass  through  definite 
special  or  determining  points  with  transition  regions  between. 
This  difference  is  formulated  in  another  way  in  the  statement 
that  variation  in  quality  is  variation  in  kind,  while  variations  in 
intensity,  duration,  and  extensity  are  not  in  themselves  varia- 
tions in  kind. 

As  regards  the  physiological  concomitants  of  at  least  five  of 
these  characters  of  simple  sense  objects,  we  can  speak  with 
confidence.      Quality  is   essentially  correlated  with    the    kind 


290  DR.   KNIGHT  DUNLAP. 

of  end  organ  stimulated  (or  perhaps  with  the  kind  of  process 
which  is  aroused  in  the  end  organ  and  brain  cell).  Intensity  is 
correlated  with  the  intensity  of  the  process  aroused.  Duration 
is  identical  with  the  duration  of  the  process,  presumably  in  the 
central  cell.  Local  significance  is  the  correlate  of  the  particular 
end  organs  stimulated  ;  we  may  suppose  each  end  organ  to  have 
its  particular  local  sign.  Extensity  has  in  this  respect  its  full 
title  proven,  since  it  is  obviously  the  correspondent  of  the  num- 
ber of  contiguous  end  organs  stimulated. 

The  physiological  conditions  of  the  other  characters  —  feel- 
ing-tone, meaning  and  vividness  —  are  much  more  complex, 
and  hence,  though  we  assume  that  they  are  -  perfectly  definite, 
are  not  readily  assignable. 

This  scheme,  of  four  essential  characters,  and  four  which 
may  be  called  accidental.^  is  satisfactory  until  we  come  to  the 
consideration  of  sound  sensations,  at  which  point  it  seems  at 
first  unsatisfactory.  Have  we  any  character  with  which  ^itch 
can  be  identified?  Duration,  intensitjs  vividness,  feeling-tone 
and  meaning  are  of  course  excluded  from  the  possibility,  since 
they  all  apply  to  sounds  over  and  above  pitch ;  so  quality,  ex- 
tensity  and  local  significance  are  left  to  be  considered.  Quality, 
however,  is  soon  put  out  of  the  running,  since  we  have  shown 
that  in  the  other  senses  it  varies  through  various  determining 
points  which  are  few  in  number  for  each  sense ;  whereas  pitch 
varies  in  a  continuum  without  internal  orientation,  exactly  as  do 
intensity,  duration,  extensity  and  vividness.  Local  significance 
is  the  character  which  we  should  urge  in  this  connection,  if 
we  held  to  the  Helmholtz  theory  of  audition,  but  since  the 
present  disposition  is  to  look  upon  that  theory  as  mechan- 
ically untenable,  we  should  be  obliged  to  look  for  further 
reasons  for  our  choice,  and  such  reasons,  apart  from  the  neces- 
sity of  finding  some  character  with  which  the  identification  may 
possibly  be  made,  are  not  forthcoming.  On  the  contrary,  it 
seems  impossible  that  pitch  can  rest  upon  local  signs,  since  local 
signs  do  not  in  general  vary  between  two  extremes,  but  rather 
include  a  manifold  of  differences  which  do  not  admit  of  easy 
schematization.  The  same  fact  is  expressed  when  we  say  that 
intensity,  duration,  extensity,  and  likewise  pitch,  admit  of  quan- 
titative comparison,  while  local  signs  do  not. 


EXTENSITY  AND  PITCH.  29 1 

Extensity,  however,  furnishes  conditions  which  correspond 
in  every  particular  to  the  properties  of  pitch.  It  varies  con- 
tinuously between  extremes,  admits  of  quantitative  estimation 
more  or  less  exactly,  and  moreover  is  directly  connected  with 
pitch  in  introspective  analysis.  The  so-called  '  high'  notes  are 
sinall.  The  '  low  '  notes  are  large  or  voluminous.  Differences 
in  pitch,  in  other  words,  are  directly  comparable  to  differences 
in  planar  or  linear  extent,  and  the  physiological  condition  of 
difference  in  pitch  accordingly  is  probably  difference  in  number 
of  nerve-endings  stimulated.^ 

This  theory  of  pitch  is  much  more  in  accordance  with  the 
known  facts  of  tone  perception  than  is  the  Helmholtz  theory. 
Let  us  consider  first  the  discrimination  of  overtones.  Accord- 
ing to  the  local  sign  theory  there  ought  to  be  very  little  difficulty 
in  recognizing  the  octave  when  sounded  with  the  fundamental, 
for  the  two  components  are  dependent  on  the  stimulation  of  two 
nerve  endings  or  groups  of  nerve  endings  which  must  be  rela- 
tively a  considerable  distance  apart  in  the  series  and  hence  as 
easily  discriminable  as  two  points  of  light  on  the  retina.  On  the 
extensity  theory,  however,  the  nerve  endings  which  the  higher 
note  stimulates  are  all  stimulated  by  the  lower  note  ;  that  is,  the 
higher  note  is  contained  in  the  lower  note  both  psychologically 
and  physiologically,  just  as  if  a  short  streak  of  light  were  su- 
perposed on  a  long  one  ;  so  that  the  discrimination  where  the 
notes  harmonize  {i.  e.,  where  there  are  no  beats),  and  where  the 
lower  (or  larger)  note  is  not  much  less  intense  than  the  higher 
(or  smaller),  should  be  rather  difficult,  which  is  actually  the 
case. 

Moreover,  if  differences  in  pitch  depended  on  differences  in 

individual  nerve  endings  stimulated,  there  would  be  no  reason 

for  expecting  the  lower  note  in  a  complex  to  dominate,  t.  e.^  to 

give  its  pitch  to  the  complex.     But  if  the  difference  in   pitch  is 

really  a  difference  in  volume,  we  might  well  expect  the  larger 

to  determine  the  size  of  the  total  complex,  as  really  is  the  case 

when  the  lower  note  is  not  too  weak. 

1  Subsequent  to  the  construction  of  this  theory  on  purely  psychological 
grounds,  I  found  that  Ter  Kuile  had  constructed  a  physiological  theory  with 
which  it  practically  agrees.  See  Pfliiger's  Archiv,  1900,  Vol.  79,  pp.  146-157 
and  484-509. 


292  DR.  KNIGHT  DUN  LAP. 

In  the  third  place,  as  regards  a  changing  pitch,  we  have  on 
either  theory  something  analogous  to  a  perception  of  motion  ; 
but  on  the  local  sign  theory  the  analogous  motion  would  be  that 
of  a  point  generating  a  line  in  the  field  of  vision  or  of  touch ; 
while  on  the  extensity  theory  the  proper  analogy  would  be  aline 
increasing  or  decreasing  in  length  ;  /.  e.,  there  is  a  certain  part 
of  the  object  which  remains  unchanged  by  the  variation.  This 
is  a  point  on  which  introspection  may  differ  in  different  cases, 
and  on  which  it  is  hardly  trustworthy  on  account  of  the  sophis- 
tication of  our  auditory  sense  ;  in  my  own  observation,  however, 
the  shrinking  or  expanding  in  linear  extension  in  the  field  of 
vision  or  touch  is  a  perfect  analogue  of  the  shifting  pitch,  and 
the  moving  point  is  not  at  all  applicable. 

Finally,  the  peculiarities  of  the  complex  sound  we  call '  noise , 
fit  in  perfectly  with  the  proposed  theory.  The  analytic  char- 
acteristics of  a  '  noise '  are  :  (i)  excessive  complexity,  which  is 
the  essential  feature,  and  may  be  the  only  one  except  for  the 
beats  to  which  it  gives  rise ;  (2)  progressive  variation  in  the  in- 
tensity and  pitch  of  the  components,  which  is  an  accidental 
feature,  but  which  adds  greatly  to  the  '  noisiness ' ;  and  (3)  in- 
definiteness  in  pitch  of  the  complex  determined  by  the  first  two 
characteristics. 

The  reason  for  this  indefinitness  of  pitch  becomes  clear  as 
soon  as  we  consider  the  analogy  to  light  sensations.  Suppose 
we  superpose  many  streaks  of  light  of  various  lengths,  making 
one  end  of  each  streak  coincident  with  the  corresponding  ends 
of  all  the  others.  The  result  will  be  a  streak  of  light  relatively 
very  intense  at  one  end  and  fading  off  at  the  other,  so  that  the 
length  of  the  total  illuminated  area  is  indefinite.  This  is  just 
what  happens  in  the  case  of  a  noise ;  the  superposition  of  the 
variety  of  tones  makes  the  exact  limits  of  the  complex  difficult  of 
determination,  although  there  is  a  general  ^lich.  distinguishable. 

The  designation  of  pitch  as  the  form  which  extensity  takes 
in  auditory  sensation  seems  to  be  the  most  satisfactory  clearing 
up  of  the  field  of  sensation  characters.  Not  onl}'^  does  it  dis- 
pose of  the  vexed  question  of  pitch,  but  it  also  helps  to  confirm 
the  right  of  extensity  to  be  considered  an  essential  character  of 
sensation,  instead  of  an  accidental  character. 

*  The  MS.  of  this  article  was  received  February  2,  '05. — Ed. 


llnlvefsitj  of  Umm 

Psycbological  Laborstor). 


[Reprinted  from  the  Psychological  Review.  Vol.  XVII.,  No.  4,  Julj,  1910.] 


FROM   THE   UNIVERSITY   OF   CALIFORNIA 
PSYCHOLOGICAL   LABORATORY. 

XL    Experiments  on  the  Reproduction  of  Distance  as 
Influenced  by  Suggestions  of  Ability  and  Inability. 

BY  GRACE  MILDRED  JONES,  M.h- 

Up  to  the  present  time  the  several  experiments  to  determine 
the  effect  of  suggestion  have  been  made  with  some  important 
differences  in  the  method  of  investigation.  In  the  earlier  experi- 
ments the  observer  was  given  no  instructions  to  resist  any  in- 
fluence by  suggestion  ;  as,  for  example,  in  Small's  ^  test,  where 
a  visual  illusion  was  employed  and  the  children  given  no  warning 
of  such  ;  so  in  Binet's^  experiment  where  the  subjects  were  mis- 
informed as  to  the  true  length  of  the  lines  in  their  relation  to 
one  another.  The  experiments  of  Pearce,^  and  of  Smith  and 
Sowton  *  were  made  under  practically  these  same  conditions. 

With  Brand  ^  a  radically  new  method  was  adopted.  The 
subjects  were  aware  of  the  purpose  of  the  experiment  and  while 
the  content  of  the  suggestion  was  to  be  given  place  in  the  mind 
the  observers  were  warned  against  any  voluntary  response  to  it. 
Furthermore,  the  reactions  depended  not  alone  upon  visual 
perception  but  primarily  upon  the  power  to  reproduce.  Bell's  ^ 
experiment  in  these  essential  conditions  was  identical  with 
Brand's.  It  differed  chiefly  in  this  :  that  a  visual  type  of  sug- 
gestion was  used  in  addition  to  the  vocal. 

In  the  present  investigation,  the  method  in  general  remained 

^ Small,  'The  Suggestibility  of  Children,'  Pedagog.  Sent.,  1896,  IV.,  pp. 
176-220. 

*  Binet,  La  suggestibilite,  Annee  Psych.  V.,  pp.  82-152. 

^  H.  J.  Pearce,  'Normal  Motor  Suggestibility,'  Psych.  Rev.,  1902,  IX.,  pp. 
329-356. 

*  W.  J.  Smith  and  S.  C.  M.  Sowton,  'Observations  on  Spatial  Contrast  and 
Confluence  in  Visual  Perception,'  Brit.  J.  Psych.  ^  '^'^'^li  H-)  PP-  196-219. 

^J.  E.  Brand,  'The  Effect  of  Verbal  Suggestion  on  the  Estimation  of  Linear 
Magnitudes,'  Psych.  Rev.,  1905,  XII.,  pp.  41-49. 

^  J.  C.  Bell,  'The  Effect  of  Suggestion  upon  the  Reproduction  of  Triangles 
and  Point  Distances,'  American  Journal  of  Psychology,  1908,  XIX.,  pp.  504-518. 

369 


llnlverslty  of  California 


270  GRACE  MILDRED  JONES. 

the  same  as  with  Brand.  The  nature  of  the  suggestions  was 
changed  and  instead  of  being  given  in  the  form  of  a  command 
they  conveyed  ideas  of  ability  and  inability.  The  chief  differ- 
ence lay  in  the  fact  that  three  types  of  suggestion  were  used, 
the  vocal,  the  visual,  and  the  'auto,'^  and  that  a  special  investi- 
gation was  made  of  the  relative  effect  of  these  various  types. 

Method  of  Experiment. 

The  apparatus  employed  in  the  present  experiment  was 
almost  identical  with  that  used  by  Brand.  At  a  distance  of  80 
centimeters  from  the  subject  two  white  pegs  were  set  up  show- 
ing through  a  narrow  slit  in  a  black  screen  ;  below  this  slit  was 
another,  somewhat  wider,  in  which  were  exposed  the  visual 
suggestions.  It  was  so  arranged  that  the  slits  might  be  covered 
and  uncovered  conveniently  to  meet  the  needs  of  the  experi- 
ment. At  a  distance  of  40  centimeters  from  the  observer  was 
another  black  screen  low  enough  so  that  the  subject  was  able  to 
see  the  horizontal  slits  in  the  farther  screen  where  the  pegs 
fixing  the  standard  distance  were  exposed.  On  the  nearer 
screen  was  a  ledge  where  the  subject  was  to  adjust  correspond- 
ing pegs  in  making  his  '  reproduction.'  Both  screens  were 
built  upon  a  table  at  a  convenient  level ;  the  background  was 
black  and  the  room  but  dimly  lighted.  The  pegs  themselves 
were  made  clearly  visible  by  screened  lights. 

The  observer  responded  to  six  varieties  of  suggestion  and 
to  one  signal  where  no  suggestion  was  offered.  Three  types  of 
suggestion  were  used  —  the  visual,  made  by  means  of  the  printed 
mottoes  "You  are  now  able"  and  "You  are  now  unable"; 
the  vocal,  made  by  the  experimenter  to  the  observer  in  the  same 
words ;  and  the  '  auto,'  made  by  the  subject  to  himself  in  the 
words,  "  I  am  now  able  "  ;  "I  am  now  unable."  The  sugges- 
tions were  given  in  irregular  order ;  after  each  an  interval  of  a 
second  and  a  half  was  allowed  before  the  exposure  of  the  pegs, 
to  give  the  subject  time  to  concentrate  his  attention  on  the  idea. 
The  pegs  were  then  exposed  for  a  second  and  a  half,  the  slide 
was  replaced  so  as  to  conceal  them,  and  the  observer  immediately 

^ '  Auto  '  is  the  name  given  to  the  type  in  which  the  observer  responded  to 
his  own  suggestion  of  ability  or  inability. 


THE  REPRODUCTION    OF  DISTANCE.  27 1 

placed  his  pegs  upon  the  ledge  and  adjusted  them  in  accordance 
with  his  estimate  of  the  distance  between  the  exposed  pegs. 
This  distance,  or  space  interval,  was  kept  constant  throughout 
the  experiment ;  but  of  this  the  subjects  were  unaware,  as  their 
assertions  prove.  Each  of  the  subjects  took  it  for  granted, 
when  the  absolute  position  of  the  pegs  was  changed,  which 
occurred  after  every  sixth  judgment,  that  the  space  interval 
was  changed  also. 

The  experiment  covered  a  period  of  five  months,  from 
October,  1908,  to  March,  1909;  during  this  time  the  subjects 
were  experimented  upon  at  regular  intervals  and  were  required 
to  give  approximately  the  same  number  of  judgments  at  each 
sitting.  Three  observers,  experienced  in  psychological  methods, 
were  engaged.  Five  hundred  twenty-five  estimates  were  made 
by  each  of  the  three  subjects ;  that  is,  seventy-five  estimates 
for  each  variety  of  suggestion  and  seventy-five  with  no  sugges- 
tion. The  subject  was  instructed  to  allow  each  suggestion  a 
place  in  his  mind,  to  hold  the  idea  it  offered,  but  not  to  allow 
it  consciously  or  intentionally  to  affect  his  estimate.  Toward 
the  close  of  the  experiment  each  observer  reported  that  he  felt 
certain  he  was  not  being  influenced  in  the  least  degree  by  any 
of  the  types  of  suggestion.  According  to  their  statements  no 
feelings  of  ability  or  inability  were  aroused  within  them,  nor 
was  the  experimenter  able  to  observe  any  outward  effect,  such 
as  hesitation  or  the  like. 

Results. 
In  that  portion  of  Table  I.  which  presents  the  averages  for 
the  combined  seventy-five  estimates  the  results  are  seen  to  be 
uniform  for  all  the  three  subjects  in  these  respects,  that  in  all 
twenty-four  '  groups'^  where  the  affirmative  of  any  type  is  com- 
pared  with  the  negative  of  the  same   type,  both  the  constant 

'  'Group'  is  used  here  and  throughout  the  account  to  mean  a  pair  of  averages, 
namely  the  affirmative  and  negative  of  any  single  type  of  suggestion  or  of  the 
combined  types  —  and  this,  either  as  regards  average  reproduction  (or  the  con- 
stant error)  or  variability.  For  example,  in  Table  I.,  in  the  first  series  of 
twenty-five  judgments,  30.88  and  30.34  constitute  a  'group'  for  subject  X;  1.52 
and  1.58  another  group  for  the  same  subject.  Thus  for  each  series  of  twenty- 
five  judgments  there  are  eight  groups  for  each  subject,  making  twenty-four  for 
the  three  subjects  for  that  series. 


272 


GRACE  MILDRED  JONES. 


error  ^  and  the  variability  ^  are  appreciably  less  with  the  affirma- 
tive suggestions  than  with  the  corresponding  negative  sugges- 
tions. And  again,  in  the  averages  obtained  from  judgments 
made  with  no  suggestion  there  is  always  less  constant  error  and 
usually  less  variability  than  in  any  of  the  averages  of  estimates 
with  suggestion. 

Table  I. 
The  Average  Reproduction  of  the  Standard  Distance  (30  cm.  ) 

TOGETHER  WITH  THE  VARIABII^ITY. 
(The  latter  given  in  each  case  immediately  below  the  average  reproduction.) 


Averages  for  First 

Averages  lor  Second 

Averages  for  Third 

Averages  for  Com- 

25 Judgments. 

25  Judgments. 

25  Judgments. 

bined  75  Judgments. 

Type  of  Suggestion. 

Subject 

Subject 

Subject 

Subject 

X. 
30.88 

Y. 

Z. 

X. 

Y. 

z. 

X. 

Y. 

z. 

X. 

Y. 

Z. 

Visual  —   affirma- 

30-4 

33-64 

28.66 

30-50 

30.38 

27.12 

30.70 

30.86 

28.886 

30.533 

31.626 

tive 

1-52 

1.64 

3-68 

1.74 

.86 

1.04 

2.88 

-94 

1.42 

2.046 

1. 146 

2.046 

Visual  —  negative 

30-34 

30.08 

33-56 

28.30 

31-04 

30.48 

26.82 

30.S4 

31.08 

28.486 

30.653l3i.706 

1.58 

2.04 

3-72 

1-9 

1.48 

1.36 

3-18 

1.08 

1.56 

2.22 

1-533 

2.213 

Vocal   —   affirma- 

30-94 

30.06 

33-18 

29.16 

30.64 

30.06 

27-75 

30.68 

31.06 

29.28 

30.46 

31-433 

tive 

1-34 

1.34 

3-3 

1.36 

1. 12 

1. 10 

2.32 

1.08 

1-54 

1.673 

1. 18 

1.98 

Vocal  —  negative 

31.10 

30.58 

33-40 

28.382 

30-90 

30.50 

23.74 

31.02 

31.46 

27-78 

30.83331.786 

1-9 

1.66 

3-64 

1-7 

I.I 

1.54 

2.26 

1.38 

1.62 

1-953 

1.38      2.266 

Auto. —  affirmative 

30.72 

30.06 

32.96 

28.46 

30.48 

30.16 

27.74 

30.88 

31-76 

28.973 

30.47331.626 

1.76 

1.02 

3.28 

1.66 

.84 

.88 

2.3 

1. 12 

1.76 

1.906 

-993!   1-973 

Auto.  —  negative 

30.88 

30.28 

32.8S 

28.54 

30.50 

30.70 

27.40 

30.74 

31.48 

28.94 

30.50631.686 

1.6 

1.6 

3.12 

1.62 

1.54 

1.50 

2.6 

1. 14 

1.96 

1-94 

1.426^  2.193 

No  suggestion 

31.24 

29.76 

32.66 

29.32 

30.52 

30.24 

28.16 

30.72 

31.28 

29-573 

30-333;  3 1. 393 

1.72 

1.72 

2.74 

1.24 

.92 

1.64 

2.04 

1.0 

1.52 

1.666 

1. 213    1.966 

^All  types  of  sug- 

30.81 

30.243 

33-27 

28.583 

30.676 

30.38 

26.761 

30.81 

31-283 

28.724 

30.57631.643 

gestion  combined 

1.616 

1-55 

3-456 

1.663 

1. 156 

1.236 

2.59 

1.123 

1.643 

1-956 

1.276 

2. 112 

Affirmative     sug- 

30.846 

30.173 

33-26 

28.76 

30.533 

30.20 

27.54 

30.753 

31.226 

29.048 

30.488 

31-561 

gestions  combined 

1.54 

1-333 

3-42 

1-56 

-94 

I.O 

^•5„ 

1.046 

T.57 

1-875 

1. 106 

2.0 

Negative     sugges- 

30.773 

30.313 

33-28 

28.406 

30.813 

30.56 

25.98 

30.866 

31-34 

28.388 

30.664 

31.726 

tions  combined 

1.693 

1.766 

3-49 

1-74 

1-373 

1.46 

2.68 

1.2 

1.71 

2.037 

1.446 

2.224 

Visual  suggestions 

30.61 

30.24 

33-60 

28.48 

30-77 

30.43 

26.96 

30.77 

30.97 

28.686 

30.593 

31-66 

combined 

1-55 

1.84 

3-70 

1.82 

1.17 

1.2 

3-03 

I.OI 

1.49 

2.133 

1.34 

2.13 

Vocal   suggestions 

31.02 

30.32 

33-29 

28.77 

30-77 

30.28 

25-75 

30.85 

31-26 

28.513 

30.646 

31.61 

combined 

1.62 

1.5 

3-47 

1-53 

I. II 

1.32 

2.29 

1.23 

1.58 

1.813 

1.28 

2.12 

Auto,    suggestions 

30.80 

30.17 

32.92 

28.50 

30.49 

30.43 

27-57 

30.81 

31.62 

28.956 

30.49 

31-65 

combined 

1.68 

I-3I 

3.20 

1.64 

1. 18 

1. 19 

2.45 

I-I3 

1.86 

1.923 

1. 21 

2.083 

^The  'constant  error'  is  the  difference  between  the  standard  distance  (30 
cm. )  and  the  '  average  reproduction  ' — the  latter  being  the  average  of  the  actual 
estimates  made.  Thus  the  '  average  reproduction  '  for  the  three  estimates  33, 
28  and  31  would  be  30.67  ;  the  '  constant  error  '  0.67. 

^'Variability'  (^the  'crude  variable  error')  was  obtained  by  adding  the 
amount  of  variation  from  the  standard  (30  cm.),  regardless  of  its  sign,  and  divid- 
ing by  the  number  of  cases  considered  ;  thus  the  '  variability '  for  the  three 
judgments  33,  28  and  31  would  be  2. 

3  "  All  types  of  suggestion  combined  "  excludes  throughout  estimates  with 
no  suggestion. 


THE  REPRODUCTION   OF  DISTANCE. 


273 


Table  II. 

As  Regards  the  Average  Reproductions. 
I.  Average  Reproductions  Compared  with  the  Actual  Distance  Exposed. 


Subject. 


X 

V 


First  25  Judg- 
ments. 


Reprod.  Dist.  > 

"     > 

(except  '  no  sug- 
gestion ') 
Reprod.  Dist.  > 


Second  25  Judg- 
ments. 


Reprod.  Dist.  < 


> 


Third  25  Judg- 
ments. 


Reprod.  Dist.  < 
"      > 


> 


Entire  75  Judg- 
ments. 


Reprod.  Dist.  < 


"      > 


2.  Average  Reproductions  with  no  Suggestion  Compared  with  Average  Re- 
productions with  Suggestion  of  any  Kind. 


X 

no  sug.  > 

no  sug.  ■< 

no  sug.  ■< 

no  sug.  < 

V 

"     "     <^ 

"      "     < 

"      "     < 

"      "     < 

(except  3  affirm. 

(except  visual  -f 

(except  visual  -|- 

cases  and  visual  — ) 

and  auto. -j- and  — ) 

and  vocal  + ) 

z 

no  sug.  < 

no  sug.  < 

(except  vocal  + 

auto.  + ) 

no  sug.  •< 

(except  visual  -)- 

vocal  + ) 

"      "     < 

3.  Ave7'age  Reproductions  with  Affirmative  Suggestion  Compared  with 
Average  Reproduction  with  Negative  Sztggestion. 


X 


Y 


vis.  +  >  vis.  — 
voc.  +  <C  voc  — 
auto. -f- <^  auto. - 

vis.  +  >  vis.  — 
voc.  +  <;  voc.  — 
auto .  +  <^  auto.  — 

vis.  -f  >  vis.  — 
voc.  +  <^  voc.  — 
auto. -f>  auto. — 


vis.  +  <  vis.  — 
voc.  +  <^  voc.  — 
auto. +>  auto.— 

vis.  +  <  vis.  — 
voc.  +  <^  voc.  — 
auto. -|-<;  auto. - 

vis.  +  <<  vis.  — 
voc.  -\-  <  voc.  — 
auto. +  <  auto. - 


vis.  +  <  vis.  — 
voc.  4-  <  voc.  — 
auto. -|-<C  auto.— 

vis.  +  <^  vis.  — 
voc .  +  <C  voc. — 
auto. +  <;  auto.— 

vis.  +  <  vis.  — 
voc.  +  <;  voc.  — 
auto. +  >  auto. - 


vis.  +  <  vis.  — 
voc.  +  <C  voc.  — 
auto.  -|-<Cauto.— 

vis.  +  <C  vis.  — 
voc.  -f  <^  voc.  — 
auto.  +  <  auto.  - 

vis.  -f-  <C  vis.  — 
voc.  +  <^  voc.  — 
auto. +  <  auto. - 


As  Regards  Variability. 

4.   Variability  when  there  was  no  Suggestion  Compared  with  that  when  there 
was  Suggestion  of  any  kind. 


Subject. 


X 


First  25  Judg- 
ments. 


no  sug.  >  (ex- 
cept vocal  — 
and  auto.+  ) 

no  sug.  > 


Second  25  Judg- 
ments. 


no  sug.  < 


no  sug.  <  (ex- 
cept visual  + 
and  auto,  -f) 

no  sug.  > 


Third  25  Judg- 
ments. 


no  sug.  < 


no  sug.  <  (ex- 
cept visual  -|-) 


no  sug.  <  (ex- 
cept visual  +) 


Entire  75  Judg- 
ments. 


no  sug.  < 


no  sug.  <  (ex- 
cept visual  +, 
vocal  +,  auto 

+  ) 
no  sug.  < 


274 


GRA  CE  MILDRED  JONES. 


Table  II.      Continued. 

Vanability  when  there  was  Affirmative  Suggestion  Compared  with  that 
when  there  was  Negative  Suggestion. 


X 


Y 


vis.  +  <  vis.  — 
voc.  +  <  voc- 
auto.  +  >auto. 

vis.  +  <vis.— 
voc.  -j-  <  voc.  - 
auto.+  <  auto. 

vis.  +  <  vis. — 
voc.-j-  <  voc. — 
auto.-|-<  auto. 


vis.  +  <  vis.^ 
voc.  +  <  voc.  — 
auto.  +  >  auto.— 

vis.  +  <  vis. — 
VOC.4-  <  voc.  — 
auto. -}-<  auto.— 

vis.  +  <  vis.  — 
voc.  +  <  voc.  — 
auto.  +<  auto. — 


vis.  +<  vis.  — 
voc.  +  >'voc.  — 
auto,  -j-  <  auto.- 

vis.  +  <  vis.  — 
voc.  +  <  voc.  — 
auto. +<  auto.- 

vis.  +  <  vis.  — 
voc.  +  <  voc.  — 
auto,  -f  <  auto.- 


vis.  +  <  vis.  — 
voc.  +  <  voc.  - 
auto. -|-<  auto. 

vis.  +  <  vis.  — 
voc.  -f-  <  voc- 
auto.  4-<auto.- 

vis.  +  <  vis.  — 
voc.  +  <  voc.  - 
auto. -t-  <auto.- 


In  the  portion  of  Table  I.  which  presents  the  averages  for 
the  three  successive  series  of  twenty-five  judgments,  as  we  might 
expect,  this  general  contrast  in  the  effect  of  affirmative  and 
negative  suggestions  appears  somewhat  less  regularly ;  yet  the 
general  result  of  combining  the  entire  75  judgments  under  any 
one  type  of  suggestion  is  seen  to  be  fairly  well  distributed  over 
these  smaller  series. 

Thus  in  the  averages  for  the  first  series  of  twenty-five  esti- 
mates seven  out  of  the  twenty-four  groups  showed  a  reversed 
effect  for  the  affirmative  and  negative  suggestions,  that  is,  the 
negative  had  less  average  error  or  variability  than  the  affirma- 
tive ;  five  of  these  irregularities  were  as  regards  the  error,  the 
other  two  as  regards  the  variability.  In  the  second  series  of 
twenty-five  estimates  three  of  the  twenty-four  groups  were  irreg- 
ular, one  in  respect  to  the  error,  the  other  two  in  respect  to  the 
variability.  In  the  third  series  of  twenty-five  estimates,  three 
irregularities  out  of  the  twenty-four  groups  again  occurred,  two 
as  regards  the  error  and  one  as  regards  the  variability. 

Accordingly,  out  of  the  sevent3^-two  groups,  when  the  judg- 
ments were  considered  in  series  of  twenty-five,  there  were  thir- 
teen irregular  groups.  Of  these  thirteen  irregularities  seven 
were  with  the  '  auto '  type  of  suggestion,  three  were  with  the 
visual,  two  with  the  vocal,  and  one  appeared  in  the  comparison 
of  *  affirmative  suggestions  combined '  and  '  negative  sugges- 
tions combined,'  in  the  first  twenty-five  estimates. 

As  regards  the  smaller  constant  error  in  the  estimates  made 
with  no  suggestion  than  with  those  where  there  was  suggestion, 


THE  REPRODUCTION  OF  DISTANCE.  275 

the  results  apparent  in  the  combined  seventy-five  judgments 
appear  also  in  each  of  the  series  of  twenty-five  judgments,  save 
for  subject  X  in  the  first  series.  As  regards  the  smaller  varia- 
bility with  no  suggestion,  exceptions  occur  in  both  the  first  and 
second  series  of  twenty-five  judgments,  but  none  in  the  third 
series. 

In  view  of  the  fact  that  the  judgments  made  under  sugges- 
tion whether  affirmative  or  negative  show  so  frequently  an 
increase  in  variability  and  error  beyond  that  in  the  judgments 
made  without  suggestion,  we  may  infer  that  suggestion  does  in 
itself,  and  apart  from  the  actual  *  contents  '  of  the  suggestion, 
effect  some  change  in  the  reproduction  of  distance. 

But  it  is  also  significant  that  the  suggestion  acts  to  a  consid- 
erable extent  in  a  direction  corresponding  to  the  actual  '  con- 
tents'  of  the  suggestion  given;  /.  e.,  the  error  and  variability 
under  suggestions  of  ability  were  almost  always  less  than  when 
suggestions  of  inability  were  made. 

Previous  experimenters  found  that  one  subject  differed  from 
another  radically  in  the  degree  and  nature  of  the  change  which 
suggestion  produced.  This  is  true  only  within  somewhat  narrow 
limits,  in  the  present  experiments.  The  three  subjects  showed 
the  same  significant  tendencies  in  responding  to  suggestion  ;  that 
is,  with  each,  the  suggestions  of  ability  produced  generally  less 
error  and  less  variability  than  did  the  suggestions  of  inability ; 
and  estimates  with  no  suggestion  were  in  each  case  still  nearer 
the  standard.  The  only  difference  lay  in  the  fact  that  with  two 
of  the  subjects  there  was  a  constant  tendency  to  lengthen,  with 
the  other  subject  to  shorten,  the  reproductions  of  the  standard 
interval  of  30  cm.  And  this  constant  error,  whatever  its  direction, 
was  increased  by  suggestions,  especially  by  those  of  '  inability.' 
It  would  be  unjustifiable  to  say  that  one  observer  showed  more 
susceptibility  to  suggestion  than  another  merely  upon  the  ground 
of  a  different  direction  or  a  different  absolute  amount  in  his 
departure  from  the  standard.  Rather  the  subjects  should  be 
compared  upon  a  basis  of  the  change  in  the  amount  or  direction 
of  the  errors  or  variability  according  as  suggestions  were  present 
or  absent,  or  according  as  one  form  of  suggestion  or  another 
was  employed.  Upon  this  basis  (see  Table  III.)  there  appears 
some  difference  between  the  three  subjects. 


276  GRACE  MILDRED  JONES. 

Table  III. 

Order  of  the  Effectiveness  of  Suggestion. 

Based  upon  seventy-five  judgments  for  each  type  of  suggestion. 

/.  As  3feasured  by  the  Change  in  the  Average  Reproductioti. 

(The  types  of  suggestion  decrease  in  effectiveness  from  left  to  right.) 

Subject. 

X     Voc.  —    Vis.  —     Vis.  +     Auto.  —     Auto.  +     Voc.  +     No  suggestion 

Y  Voc.  —    Vis.  —     Vis.  +     Auto.  —     Auto.  +     Voc.  +     No  suggestion 
Z     Voc.  —    Vis.  —    Auto.  —  Auto.  +     Vis.    +     Voc.  +     No  suggestion 

//.  As  Pleasured  by  the  Change  in  Variability. 

(The  types  of  suggestion  decrease  in  effectiveness  from  left  to  right.) 
Subject. 

X    Vis.  —    Vis.  +     Voc.  —    Auto.  —    Auto.  +    Voc.  +       No  suggestion 

Y  Vis. —    Auto. —  Voc. —    No  sug.     Voc.  +      Vis.  +        Auto.  + 

Z     Voc.  —  Vis.  —     Auto.  —  Vis,  +        Voc.  +      Auto.  +     No  suggestion 

Bell  in  his  experiment  notes  that  the  effect  of  suggestion 
decreased  with  repetition.  This  seems  to  be  only  partly,  if  at 
all,  true  here.  If  the  fact  that  suggestions  of  ability  produce 
less  error,  and  suggestions  of  inability  greater  error  in  the  re- 
production of  distance  attests  anything  as  to  the  power  of  sug- 
gestion this  experiment  shows  that  the  susceptibility  more 
regularly  occurs  with  repetition,  since  as  the  experiment  pro- 
ceeds there  occur  fewer  groups  where  this  effect  is  reversed. 
Table  I.  shows  seven  irregularities  in  this  respect  in  the  first 
series  of  twenty-five  estimates,  and  three  each  in  the  second  and 
the  third  series  of  twenty-five  estimates.  Apart  from  irregu- 
larity, the  absolute  amount  of  the  difference  between  '  affirma- 
tive suggestions  combined'  and  '  negative  suggestions  combined  ' 
shows  in  the  case  of  Subject  X  a  uniform  increase  in  the  suc- 
cessive series  of  twenty-five  judgments ;  and  the  same  is  true 
of  the  difference  between  '  no'  suggestion '  and  '  all  types  of 
suggestion  combined.'  With  the  other  subjects  there  is  neither 
a  uniform  increase  nor  decrease. 

The  purpose  of  the  experiment  was  only  in  part  to  investigate 
the  effect  of  suggestion  in  general ;  to  determine  the  relative 
influence  of  the  different  tyfes  of  suggestion  was  equally  the 
purpose. 

In  Tables  III.  and  IV.  is  set  forth  the  relative  strength  or 
effectiveness  of  these  different  types  of  suggestion.  It  there 
appears  that  for  each  of  the  subjects  the  negative  suggestions 


THE  REPRODUCTION   OF  DISTANCE. 

Table  IV. 


277 


Type  of  Suggestions. 

Ratios  of  Reproductions  with  Sug- 
gestion to  Reproductions  With- 
out.    Based  upon  the  Constant 
Error  in  Reproduction  and  also 
upon  the  Variability  ;  I,atter  in 
Parentheses. 

Subject 

Ratios  of  Reproductions 
with    Suggestion    to 
the  Actual  Standard 
(30cm.).    Based  upon 
the  Error  in  Repro- 
duction. 

Subject 

X. 

y- 

z. 

X. 

K. 

Z. 

All  types  of  suggestion  com- 
bined.   (450  reproductions) 

Affirmative  suggestions  com- 
bined.  (225  reproductions) 

Negative  suggestions  com- 
bined.  (225  reproductions) 

Visual  suggestions  com- 
bined.   (150  reproductions) 

Vocal  suggestions  combined. 
(150  reproductions) 

Auto,  suggestions  combined. 
(150  reproductions) 

.971 

(I-I74) 
.982 

(i^i25) 

•959 

(1.222) 

-970 
(1.280) 

.964 
(1.088) 

•979 
(i^i54) 

1.008 

(1-051) 
1.005 

(•911) 

l.OIO 

(1.192) 

1.008 

(1. 104) 

l.OIO 

(1-055) 
1.005 

(-997) 

1.007 
(1.074) 

1.005 
(I. 017) 

l.OIO 

(1-131) 

1.008 

(r-083) 

I.C06 

(1.078) 

I.ooS 
(1-059) 

-957 
.968 
.946 
.956 
•950 
•965 

1. 019 
1. 016 
1.022 
1. 019 
1. 021 
1. 016 

1-054 
1.052 

1-057 
1-055 
1-053 
1^055 

(suggestions  of  inability)  were  about  twice  as  effective  as  were 
the  positive  suggestions  (suggestions  of  ability).  Moreover  for 
each  subject  the  vocal  negative  suggestions  were  the  most  effec- 
tive of  all  as  measured  by  the  constant  change  in  the  average 
reproduction.  As  measured  by  the  variability,  the  visual  nega- 
tive suggestions  were  stronger.  With  all  the  subjects  the  vocal 
positive  suggestions,  on  the  other  hand,  had  the  least  influence 
upon  the  average  reproduction  ;  while  upon  the  variability  the 
*  auto '  positive  type  was  among  those  having  the  weakest 
influence. 

As  suggestions  of  ability  and  inability  appeared  to  bring 
about  an  increase  in  the  constant  error  and  in  the  variability  the 
question  was  raised  as  to  whether  the  results  were  due  merely  to 
the  distraction  which  the  suggestions  produced,  and  not  at  all 
to  their  inherent  '  content '  or  ideas.  It  hardly  seemed  that 
such  a  theory  could  be  fully  justified,  for  it  would  not  account 
for  the  fact  that  different  types  of  suggestion  had  regularly 
produced  different  effects  —  effects  consistent  with  the  '  content' 
of  the  suggestion.  However,  seventy-five  additional  tests  were 
made  on  each  of  the  three  subjects,  in  which  the  pegs  were  ex- 
posed and  the  reproductions  made  while  the  observer  counted 
aloud  the  strokes  of  a  metronome,  swinging  at  five  different 
rates,  in  order  that  the  counting  might  more  likely  act  as  a  dis- 


278 


GRACE  MILDRED  JONES. 


traction  and  not  become  a  merely  mechanical  operation.  The 
other  conditions  were  identical  with  those  in  the  tests  made  for 
suggestibility. 

Table  V. 
Results  for  Estimates  made  under  Distraction. 


Average  Reproductions  of  the  Standard  Distance  together  with  the  Variability. 

Subject. 

Averages  for  First 

Averages  for  Second 

Averages  for  Third 

Averages  for  Com- 

25 Judgments. 

25  Judgments. 

25  Judgments. 

bined  75  Judgments. 

X 

28.48 

28.32 

28.12 

28.31 

1.68 

1.64 

1.88 

1-73 

V 

29.86 

29.38 

29-15 

29.48 

■94 

.86 

•93 

.89 

z 

29.  tS 

29.14 

31-65 

29.92 

1.02 

1-54 

1.88 

1.46 

The  variability  is  thus  seen  to  be,  on  the  average,  less  than 
when  suggestions  were  offered,  and  for  the  most  of  the  subjects 
less  even  than  in  the  cases  where  no  suggestion  was  made.  As 
for  the  average  reproductions,  the  two  subjects  whose  esti- 
mate of  the  distance  had  been  constantly  greater  than  the 
standard  in  the  previous  experiment  now  had  a  tendency  to  make 
it  less  than  the  standard.  The  other  subject  whose  tendency 
had  been  to  underestimate  the  standard  interval  now  had  a  ten- 
dency to  make  it  still  shorter. 

The  fact  that  the  results  with  distraction  differed  in  these 
respects  from  the  results  with  different  types  of  suggestion  indi- 
cates that  at  least  with  two  of  the  three  subjects  the  peculiar 
effect  of  these  suggestions  is  not  due  solely  nor  even  pre- 
dominately to  any  distraction  which  may  have  inhered  in  them. 


Onl»ersitf  of  California 

PsynliiilojKal  aoratoi). 


l^ 


THE  EFFECT    OF    VARIOUS    TYPES  OF  SUGGESTION 
UPON  MUSCULAR  ACTIVITY 


BY  EDW.  K.  STRONG,  Jr.,  M.S. 


Reprinted  from  the  Psychoi^ogical  Review,  July,  1910, 
Vol.  XVII,  pp.  229-259. 


Oolvefsify  of  Oaiifeiii- 


[Reprinted  from  The  Psychological  Review,  Vol.  XVII.,  No.  4,  July,  191 0.] 


XII.  The  Effect  of  Various  Types  of  Suggestion 
UPON  Muscular  Activity. 

BY  EDW.  K.  STRONG,  Jr.,  M.S. 

The  purpose  of  the  experiment  here  reported  was  to  discover 
how  far  and  in  what  manner  maximum  muscular  activity  may- 
be affected  by  suggestions  of  various  types.  In  all  these  the 
subject  was  instructed  not  to  oppose  any  resistance  to  the  sug- 
gestion nor  on  the  other  hand  consciously  to  endeavor  to  carry 
out  the  suggestions,  but  his  attention  and  conscious  effort 
throughout  was  to  be  expended  in  exerting  each  time  his  maxi- 
mum grip.  Yet  he  was  requested  to  maintain  the  suggestion  in 
consciousness  until  after  his  muscular  effort. 

Historical  Review. 

There  is  scarcely  any  literature  which  bears  directly  upon 
the  question  under  discussion  in  this  paper.  A  number  of 
articles  ^  which  have  appeared  lately  indicate  that  some  atten- 
tion is  being  given  the  subject,  but  neither  their  methods  nor 
their  results  have  any  direct  relation  to  those  of  the  present 
investigation.  As  far  as  I  am  aware  Brand  is  the  pioneer  in 
this  field  of  investigation.  His  experiment^  was  performed  in 
this  laboratory,  and  his  purpose,  as  he  states  it,  was  "  to  find 
out  how  far  and  in  what  direction  the  visual  estimation  of  a 
linear  magnitude  could  be  affected  by  suggestion  of  certain  pos- 
sible errors  in  such  estimation,  the  subject  knowing  that  the 

^Triplet,  '  Dynamogenic  Factors  ia  Pace-making  and  Competition,'  Amer- 
four.  of  Psych. y  IX.,  507-533.  Small,  'The  Suggestibility  of  Children,'  Ped. 
Sent.,  IV.,  182.  Binet,  'La  suggestibility,'  L'antiee  psych.,  V.,  99.  Pearce, 
'Normal  Motor  Suggestibility,'  Psych.  Rev.,  IX.,  348.  Smith  and  Sowton, 
'  Observations  on  Spatial  Contrast  and  Confluence  in  Visual  Perception,'  Brit. 
Jour.  Psych.,  II.,  J96-219.  A  very  full  discussion  of  all  but  the  first  accom- 
panies the  article  of  Bell  ('  The  Effect  of  Suggestion  upon  the  Reproduction  of 
Triangles  and  of  Point  Distances')  in  the  Avier.  Jour,  of  Psych.,  XIX.,  504. 

2  'The  Effect  of  Verbal  Suggestion  upon  the  Estimation  of  Linear  Magni- 
tudes,' Psych.  Rev.,  XII.,  1905,  41-49.3 


279 


OnlvffsiH'  ^f  California 

Psyotiologicai  liboratoi). 


28o  EBJV.    K.    STRONG. 

suggestions  were  purely  arbitrary,  /.  e.^  that  they  had  no  refer- 
ence to  any  foreseen  tendency  to  err  in  any  direction."  ^ 

The  eight  different  suggestions  used  by  Brand  in  his  experi- 
ment were  printed  upon  white  cardboard  in  letters  1.2  cm,  high. 
The  conductor  presented  them  to  the  subject  by  displaying  the 
cardboard  for  a  moment.  After  the  suggestion  had  been  pre- 
sented the  conductor  displayed  two  small  objects  upon  his  frame 
and  then  called  upon  the  subject  to  respond  by  setting  up  his  two 
similar  objects  upon  his  own  frame  at  a  distance  from  each  other 
approximating  as  nearly  as  possible  that  of  the  original  objects. 

I  have  reduced  the  results  as  given  in  his  tables  to  per- 
centages of  the  respective  standards. 

The  following  table  gives  the  total  results  of  Subject  'C,' 

eliminating  the  first  group  of  experiments,  since  their  variation 

is  more  than   ten  per  cent,  from  the  standard,  due  probably  to 

lack  of  practice. 

Table  I. 

Suggestion.  No.  of  Sum  of  Result  in 

Judgments.  Standards.  per  cent. 

Zwp  fjvic  bgzx  asye 49  1,258  100.5 

L,ife  is  real  where 49  1.258  99.5 

Don't  make  too  long 49  1,258  loi.o 

Don't  make  too  short 49  1,258  loi.o 

Make  short  104  2,632  99.5 

Makelong 104  2,632  102.0 

And  the  following  table  gives  the  total  results  for  Subject 
'  Y,'  the  first  group  of  data  having  been  likewise  eliminated. 

Table  II. 

Suggestion.  No.  of  Sum  of  Result  in 

Judgments.  Standards.  per  cent. 

Zwp  fjvic  bgzx  asye 49  1,086  91.0 

Life  is  real  where 49  1,086  90.0 

Don't  make  too  long 84  1,810  92.0 

Don't  make  too  short 84  1,810  92.5 

Make  short 100  2,400  94.0 

Makelong 100  2,400  94.0 

1  It  is  just  at  this  point  that  suggestions  as  experimented  upon  in  Bell's 
(see  page  5)  and  Brand's  work  and  in  my  own  differ  from  the  others.  As  Bell 
puts  it ;  "  The  most  potent  factor  without  doubt  in  cases  of  suggestion  is  the 
arousal  of  an  attitude  of  general  expectancy."  This  factor  has  been  utilized  in 
the  experiments  of  others,  but  is  so  far  as  possible  eliminated  in  these  three,  for 
here  the  subject  was  particularly  instructed  that  he  was  not  to  respond  con- 
sciously to  the  suggestion  but  to  endeavor  consciously  to  exert  his  maximum 

grip- 


EFFECT  OF  SUGGESTION  UPON  MUSCULAR   ACTIVITY.      281 

From  these  tables  I  do  not  feel  that  any  clear-cut  deductions 
can  be  made,  with  the  possible  exception  that  the  two  brief  sug- 
gestions '  Make  short '  and  '  Make  long '  tend  more  than  the 
other  suggestions  to  make  the  reproduced  distance  greater  in 
magnitude,  and  the  two  suggestions  '  Don't  make  too  long '  and 
*  Don't  make  too  short '  tend  to  a  less  degree  to  have  the  same 
effect. 

In  Table  III.  Brand  has  brought  together  from  group  D  (or 
the  last  group  of  experiments  with  both  subjects)  the  totals  for 
all  the  suggestions  containing  the  word  '  long'  in  one  column 
and  all  those  containing  the  word  '  short'  in  another  column,  for 
comparison.  The  percentages  as  given  below  were  inserted  by 
myself. 

Table  III. 

c„K-„„(.  No.  of  Sum  of  <T^.,^>  Per  <  ct,«..f  >  Per 

Subject.  Judgments.  Standards.  ^"'^e-  cent.  ^hort.'  ^^^^ 

'C  58  1,628  1.702.3        104.5  1)644.4  loi.o 

*Y'  36  5S0  556.3  95.5  542.6  93.5 

If  compiled  from  all  four  of  the  groups  instead  of  group  D 
alone  we  have  the  following. 

Table  IV. 

e,,K;^„»  No.  of  Sum  of  «t«^^>  Per  <ct,^..t'  Per 

Subject.  Judgments.  Standards.  ^°'^e-  cent.  ^^o'^*-  cent. 

'C  207  4,932  5,095-8       103.0         5.052.2         102.5 

•Y'  189  4,294  4,008.2  93.8  4.013-2  93.9 

Here  we  have  no  superiority  of  the  '  long '  mottoes  over  the 
'  short '  mottoes,  except  with  the  one  subject. 

Let  us  now  turn  to  the  second  part  of  his  experiment.  Here 
but  three  suggestions  were  used  :  '  long,'  '  short '  and  '  XXXX.' 
The  latter  was  used  as  a  check  or  neutral.  Quoting  from  him  : 
"  Four  subjects  were  employed  and  the  results  were  not  very  uni- 
form, two  of  the  subjects  showing  no  decided  tendency  towards 
anything  resembling  a  constant  effect,  while  the  other  two  sub- 
jects showed  a  clear  general  constancy  of  considerable  difference 
throughout." 

In  conclusion  it  seems  to  me  that  one  cannot  point  with  any 
emphasis  to  any  direct  effect  from  the  above  varied  suggestions 
upon  estimation  of  distance  except  (i)  that  '  long '  suggestions 
may  consistently  affect  one  person  more  than   corresponding 


282  EDW.    K.    STRONG. 

*  short'  ones  ;  (2)  that  the  reverse  effect  may  be  produced  upon 
a  second  person  ;  and  (3)  that  there  may  be  no  appreciable 
effect  of  one  or  the  other  upon  a  third  person. 

In  Bell's  experiment^  two  types  of  suggestion  were  used  — 
the  auditory  and  the  visual.    For  the  former  such  as  '  make  high,' 

*  make  low,'  'make  high  enough,'  etc.,  or  simply  'high'  and 
'  low  '  were  used,  being  spoken  by  the  conductor  just  before  the 
presentation  of  the  object  to  be  reacted  upon.  For  the  visual 
suggestion  a  diamond-shaped  figure  20  cm.  long  and  4  cm.  wide 
was  shown  to  the  subject.  When  displayed  in  a  vertical  posi- 
tion it  was  thought  that  it  might  serve  as  a  '  high '  suggestion, 
being  much  taller  than  an}^  other  figure  shown.  Likewise  when 
shown  in  a  horizontal  position  it  was  called  a  '  low '  suggestion. 
(As  far  as  I  am  aware  the  subject  was  not  informed  what  this 
visual  suggestion  was  intended  to  suggest.  It  may  not  then 
have  had  an  equal  effect  upon  the  different  subjects.) 

The  forms  chosen  for  reproduction  were  :  (i)  triangles  of 
different  shapes  and  heights  and  (2)  vertical  point  distances  as 
shown  by  (a)  a  dot  above  the  center  of  a  base  line  and  {b)  a  dot 
above  another  dot. 

Under  the  first  group  (triangles  of  different  shapes  and 
heights)  ten  triangles  were  used,  of  the  same  base  (10  mm.),  but 
of  different  heights  and  shapes,  and  varying  from  49  to  100  mm. 
in  altitude.  The  work  was  so  carried  on  that  nine  reproduc- 
tions of  each  triangle  were  made  with  each  kind  of  suggestion 
{i.  e.,  auditory  and  visual).  Three  of  the  nine  were  reproduced 
with  '  high  '  suggestions,  three  with  '  low  '  suggestions,  and  three 
without  any  suggestion.  The  altitude  of  the  reproduced  triangle 
was  compared  wiih  the  standard,  and  the  difference  expressed  in 
millimeters  as  a  positive  or  negative  error.  But  the  weakness 
of  his  experiment  lies  in  the  small  number  of  observations  per 
subject  per  triangle  per  suggestion,  /.  e.,  tJwee  in  number. 
Averages  drawn  from  so  few  observations  are  hardly  of  greatest 
weight. 

Bell  concludes  "  that  in  general  the  suggestions  do  affect 
the  reproduction  of   the  triangles  ;  that  the  auditory  suggestion 

1  '  The  Effect  of  Suggestion  upon  the  Reproduction  of  Triangles  and  of 
Point  Distances/  Ainer.Jour.  of  Psych.,  XIX.,  190S,  504. 


EFFECT   OF  SUGGESTION  UPON  MUSCULAR  ACTIVITY.      283 

is  more  effective  than  the  visual ;  and  that  in  the  auditory  set 
the  '  low  '  suggestion  is  more  effective  than  the  '  high.'  "  Upon 
looking  at  the  subjects  individually  we  find  they  have  reacted 
differently.  Subject  '  B  '  alone  showed  striking  susceptibility  to 
the  suggestion  in  all  the  cases.  Subjects  'A,'  'C  and  'D' 
with  the  auditory  suggestions  and  Subject  '  E  '  with  the  visual 
suggestions,  estimated  the  apex  of  the  triangles  below  the  stand- 
ard when  given  either  '  high  '  or  '  low  '  suggestions.  Through- 
out the  experiment  susceptibility  to  '  low  '  suggestions  was  more 
general  and  more  uniform  than  to  '  high '  suggestions. 

Under  the  second  group  (vertical  point  distances)  the  dot- 
above-line  experiment  was  completed  with  auditory  suggestions 
and  the  dot-above-dot  experiment  with  visual  suggestions.  Bell 
in  commenting  upon  his  results  states  that  there  was  little  indi- 
cation that  the  suggestions  had  any  constant  effect:  with  sub- 
jects '  C  '  and  *  D  '  the  '  high  '  and  '  low  '  suggestions  are  both 
lower  than  the  standard,  the  '  low  '  the  lowest ;  while  with  sub- 
jects '  E '  and  '  F  '  the  '  high  '  and  '  low '  suggestions  are  both 
higher  than  the  standard. 

Description  of  the  Present  Experiment. 

The  series  of  experiments  carried  on  as  described  below  can 
be  divided  into  two  parts,  the  first  part  consisting  of  those  ex- 
periments which  were  performed  during  the  months  from  Sep- 
tember to  December,  1908,  and  the  second  part  consisting  of 
those  which  were  performed  during  the  months  from  January  to 
April,  1909. 

The  general  plan  of  the  experiment  was  to  give  the  subject 
a  suggestion,  and  then  have  him  respond  each  time  with  his 
maximum  grip.  Collin's  elliptical  form  of  dynamometer  was 
used  and  from  it  an  expression  in  kilograms  was  obtained  of  his 
muscular  activity. 

The  subject  was  seated  in  a  chair  which  was  provided  with 
two  flat  arms  about  two  and  a  half  inches  wide  which  extended 
as  far  forward  as  the  front  edge  of  the  seat.  The  subject  rested 
his  arms  from  the  elbow  to  the  wrist  upon  these  arms  of  the 
chair.  When  actually  gripping  the  dynamometer  the  palm  of 
his  hand  was  uppermost.     In  the  intervals  he  was  allowed  to 


284  BDIV.   K.    STRONG. 

rest  his  hand  as  he  chose.  The  conductor  sat  at  a  small  table. 
On  the  edge  of  this  table  between  the  subject  and  the  conductor 
a  large  upright  black  screen  was  placed  in  such  a  manner  that 
the  subject  could  not  see  anything  upon  the  table ;  nor  could  he 
see  the  conductor. 

Once  every  twenty  seconds,  until  the  series  with  one  hand 
was  completed,  the  subject  gripped  the  dynamometer  with  his 
maximum  force.  The  exact  procedure  was  as  follows.  When 
the  second-hand  of  the  watch  indicated  the  moment  of  presen- 
tation, the  suggestion  was  given  by  the  conductor.  The 
dynamometer  was  then  placed  in  the  subject's  hand.  As  soon 
as  the  latter  had  responded  with  his  maximum  grip  the  con- 
ductor took  the  instrument  from  his  hand,  noted  the  reading, 
and  then  awaited  the  next  moment  of  presentation. 

In  all  there  w^ere  seven  suggestions  offered.  They  might  be 
classified  as  follows  : 

I.  Atidito7'y  Suggestions. 

1.  Positive,      "Now   you  can  make  it  stronger  than  usual." 

2.  Negative.  "  Now  you  can't  make  it  as  strong  as  usual." 
These  suggestions  were  presented  vocally  by  the  conductor. 

II.  Visual  Suggestions. 

1.  Positive.  A  plus  (-|-)  sign  0.4  inches  in  size  displayed 
upon  a  piece  of  cardboard  two  inches  square. 

2.  Negative.  A  minus  (— )  sign  0.4  inches  in  size  displayed 
upon  a  piece  of  cardboard  two  inches  square. 

In  giving  these  suggestions  the  conductor  placed  the  card- 
board upon  the  corner  of  the  table  in  front  of  the  subject. 

At  the  commencement  of  the  experiment  each  subject  was 
told  that  the  plus  (-|-)  sign  was  meant  to  suggest  to  him  that  he 
could  make  his  grip  stronger  than  usual  and  the  minus  (— )  sign 
was  meant  to  suggest  that  he  could  not  make  it  as  strong  as 
usual.  These  signs  were  consequently  visual  suggestions  de- 
pending on  previous  vocal  instruction. 

III.  Auto -suoorest ions .  Here  the  conductor  announced  in 
the  same  tone  and  manner  as  in  presenting  the  Auditory  Sug- 
gestions "Now  you  can  make  a  suggestion  of  your  own."  The 
subject  understood  by  this  that  he  was  at  liberty  to  suggest  to  him- 
self either  the  positive  or  negative  suggestion  and  to  designate 


EFFECT  OF  SUGGESTION  UPON  MUSCULAR  ACTIVITY.      285 

his  choice  to  the  conductor  by  audibly  announcing  it.  In  this 
case  as  soon  as  the  subject  had  announced  his  suggestion  the 
dynamometer  was  handed  him  and  the  experiments  continued 
as  usual. 

1.  Positive.  (After  suggestion  by  the  conductor,  as  above.) 
"  Now  I  can  make  it  stronger  than  usual,"  spoken  by  the 
subject. 

2.  Negative.  (After  suggestion  by  the  conductor,  as  above.) 
"Now  I  can't  make  it  as  strong  as  usual,"  spoken  by  the 
subject. 

IV.  Neutral '■Suggestion.''  This  consisted  of  the  announce- 
ment by  the  conductor  of,  '  Now,  neutral,'  and  was  intended  to 
act  merely  as  a  check  and  guide  to  what  would  be  the  exertion 
if  no  suggestion  of  any  sort  were  given. 

In  the  earlier  experiments  a  series  consisted  of  fifty-six 
experiments  or  readings,  twenty-eight  with  each  hand.  These 
twenty-eight  in  turn  consisted  of  four  each  of  the  seven  different 
suggestions.  These  twenty-eight  were  presented  to  the  subject 
in  a  haphazard  arrangement  previously  determined  upon.  All 
subjects  were  given  the  same  haphazard  arrangements  and  in 
the  same  order,  so  that  direct  comparisons  between  them  could 
be  made.  The  right  hand  in  every  case  was  experimented 
upon  first.  After  four  days'  work  with  each  subject,  ten 
neutrals  instead  of  four  were  introduced,  thus  making  a  day's 
work  or  series  consist  of  thirty-four  experiments  instead  of 
twenty-eight.  Besides  these  twenty-eight  or  thirty-four  experi- 
ments there  were  always  two  extra  neutrals  at  the  start  which 
were  for  the  purpose  of  practice  and  were  always  discarded. 

A  day's  work  with  subject  *  B  '  consisted  of  two  series  during 
one  hour,  —  that  is  to  say,  of  fifty-six  experiments  with  each 
hand  taken  in  this  manner :  twenty-eight  with  the  right  hand, 
then  twenty-eight  with  the  left  hand,  then  twenty-eight  with  the 
right,  and  finally  twenty-eight  more  with  the  left.  A  day's 
work  with  subjects  *J'  and  *  W'  consisted  of  only  one  series 
during  one  hour.  During  the  second  term  but  one  series  per 
day  was  taken  with  any  one  of  the  three  subjects.  It  should 
also  be  stated  here  that  all  three  subjects  were  familiar  with 
experimental  work. 


286  EDW.   K.    STRONG. 

The  procedure  during  the  second  term  was  exactly  the  same 
as  in  the  first  term  except  for  the  following.  Instead  of  seven 
suggestions  nine  were  employed.  The  two  auto-suggestions 
were  omitted  and  the  following  four  added.  Two  auditory  sug- 
gestions consisting  of  '  Now,  plus '  and  '  Now,  minus '  to  corre- 
spond to  the  two  visual  suggestions  employed  during  the  first 
term.  Also  two  visual  suggestions  consisting  of  the  mottoes : 
**Now  3''ou  can  make  it  stronger  than  usual  "  and  "  Now  you 
can't  make  it  as  strong  as  usual"  printed  on  cards  5.5  x  1.25 
inches.  These  visual  suggestions  were  to  correspond  to  the 
auditory  suggestions  employed  during  the  first  term.  More- 
over the  visual  suggestions  (-f)  and  (— )  were  presented  on  cards 
similar  to  those  just  described,  instead  of  on  cards  two  inches 
square.  Instead  of  28  or  34  experiments  on  each  hand  per  day 
there  were  42  such  experiments.  These  42  consisted  of  four 
each  of  the  eight  suggestions  and  ten  of  the  neutrals,  arranged 
as  before  in  a  haphazard  manner.  During  the  second  term  the 
right  hand  was  not  experimented  upon  first  each  da}'',  but  only 
in  alternation  with  the  left  hand. 

The  nine  suggestions  of  the  second  term  and  the  two  auto- 
suggestions of  the  first  term  will  be  referred  to  in  the  tables  by 
the  following  set  of  symbols. 

I.  Auditory  Suggestions  —  in  quotation  marks. 

'  Can  '  means  "  Now  you  can  make  it  stronger  than  usual." 
*  Can't'  means  *'  Now  you  can't  make  it  as  strong  as  usual." 
'  +  '  means  '*  Now  plus." 
'  —  '  means  "  Now  minus." 

II.  Visual  Suggestions  —  in  brackets. 

(Can)   means  the  motto,   "  Now  you  can  make  it   stronger 

than  usual "  printed  on  a  card. 
(Can't)    means    the   motto,    "Now  you   can't    make  it    as 

strong  as  usual "  printed  on  a  card. 
(-}-)   means  the  symbol  '  +  '  printed  on  a  card. 
(  — )   means  the  symbol  '  —  '  printed  on  a  card. 

III.  Auto-stiggestions. 

4-  Auto  means  "  Now  I  can  make  it  stronger  than  usual," 

spoken  by  the  subject. 
—  Auto  means  "  Now  I  can't  make  it  as  strong  as  usual," 

spoken  by  the  subject. 


EFFECT  OF  SUGGESTION  UPON  MUSCULAR  ACTIVITY.      2S7 

IV.  Neutral  '  Suggestion.'' 

'N'  means  "Now,  neutral." 

The  Results. 
In  the  following  two  tables  there  are  presented  the  averages 
of  48  experiments  for  each  type  of  suggestion  with  either  hand 
of  the  three  subjects,  the  numbers  indicating  in  kilograms  the 
maximal  grip. 

Table  V. 
Results  for  the  First  Term. 

The  numbers  for  the  first  six  suggestions  under  Subjects  '  B  '  and  'J  '  are  an 
average  of  48  results,  and  under  Subject  '  W '  are  an  average  of  24  results.  The 
neutrals  under  Subjects  'B  '  and  'J'  are  an  average  of  96  results  while  under 
Subject  '  W  '  they  are  an  average  of  36  results. 


Suggestions. 

Subject  'B.' 

Subject  'J.' 

Subject  'W.' 

Right. 

Left. 

Right. 

Left. 

Right. 

Left. 

'Can' 
'  Can't ' 

+  Auto. 
—  Auto. 

38.8 
38.4 
38.9 
38.6 

39.7 
39-0 

29.6 
28.9 
29.9 
29-3 
29-5 
29.9 

17.2 
17. 1 

17.7 
17. 1 

17.5 
17.I 

I5-0 

15-4 
I5-0 
14.8 
15.2 
15-3 

33-1 
33-3 
33.8 
33-5 
33-5 
33-6 

23-7 
23-4 
24.4 
24.4 
24.2 
25.6 

Average 
Neutral 

38.9 
39- 0 

29-5 
29.4 

17.2 
16.9 

15- 1 
I5-0 

33-5 
33-4 

24-3 
23-5 

Average  of  all 

38.9 

29-5 

I7.I 

I5-I 

33-5 

23-9 

Table  VI. 
Results  for  the  Second  Term. 

The  numbers  for  the  first  eight  suggestions  are  an  average  of  48  trials 
while  those  for  the  neutrals  are  an  average  of  120  trials. 


Suggestions. 

Subject  'B.' 

Subject  'J.' 

Subject  'W.' 

Right. 

Left. 

Right. 

Left. 

Right. 

Left. 

'Can' 
'  Can't ' 
(Can) 
(Can't) 

'  +  ' 
<      > 

40.3 
39-7 
39-4 
40.1 
39-6 
39-4 
39-3 
39-6 

31.8 
31-4 
31.0 

31-3 
31.2 
30.8 
•31-3 
31-3 

16.9 
16.9 
16.9 
16.8 
16.7 
16.7 
16.9 
16.7 

15.9 
16.3 
16.4 

15-9 
16.2 
•     16. 1 
16.3 
16.4 

32.8 
32.6 

32.9 
33-2 
32.2 
32.1 
32.4 
32.8 

25.1 
25-4 
25-3 
25.3 
24.8 

25-1 

25.3 
25-9 

Average 

Neutral 

39-7 
39-4 

31-3 

30.8 

16.8 
16.7 

16.2 
16.0 

32.6 
32.2 

25-3 
24.9 

Average  of  all 

39-5 

3I-I 

16.8 

16. 1 

32.5 

25.2 

288 


EDW.    K.    STRONG. 


From  these  two  tables  we  see  very  clearly  that  suggestion 
as  a  whole  heightens  the  maxima.  In  every  case,  except  for  the 
right  hand  of  subject  '  B  '  during  the  first  term,  the  average  of 
the  neutrals  for  any  of  the  three  subjects  with  either  hand  is 
less  than  the  corresponding  average  of  all  the  other  suggestions. 
The  exception  can  probably  be  explained  by  an  introspection  of 
subject  '  B '  on  March  i,  when  he  stated  that  neutrals  dX  first 
had  a  positive  effect,  that  is  to  say,  he  felt  that  then  was  a  time 
to  make  a  '  record.' 

In  the  following  two  tables  we  have  a  statement  of  the  mean 
variation  of  the  quantities  entering  into  the  preceding  tables  : 
Table  VII  stating  the  mean  variation  of  the  quantities  in  Table 
V,  and  Table  VIII  stating  those  of  Table  VI. 

Mean  Variation  Table  VII.     (First  Term.) 


Suggestions. 

Subject  'B.' 

Subject  'J.' 

Subject  'W.' 

Right. 

IvCft. 

Right. 

Left. 

Right. 

Left. 

'Can' 
'Can't' 
(  +  ) 
(-) 

+  Auto. 
—  Auto. 

1.88 
2-34 
2^59 
2.29 
2.21 
1.74 

2. .00 
1.70 
1.89 
1.84 
2.32 

1.86 

.86 

•74 

I. II 

1.04 

•93 

•93 

.96 

.87 

1.09 

•83 
.Si 
.88 

3-17 
2.77 
2.46 
2.62 
2.30 
2.26 

1.68 
1.48 
1. 71 
1.70 
1. 61 
1.98 

Average 
Neutral 

2.17 
1.94 

1-93 
1.57 

.93 
.85 

•91 

.94 

2.59 
2.99 

1.69 
2.08 

Average  of  all 

2.14 

1.88 

.92 

•91 

2.65 

i^75 

Mean  Variation  Table  VIII.     (Second  Term.) 


Suggestions. 

Subject   '  B  ' 

Subject  'J' 

Subject  '  W ' 

Right. 

Left. 

Right. 

Left. 

Right. 

Left. 

'Can' 
'  Can't ' 
(Can) 
(Can't) 

'  +  ' 
< 1 

(  +  ) 
(-) 

2.58 

2.57 
2.04 
1.80 
1.82 
2.17 
2.46 
1.97 

l^54 

1.88 

.80 

•67 
.80 
.80 
.87 
•92 

•63 
-73 
.76 
.67 
•79 
•77 
.81 
.89 

1.03 
1. 01 

•91 
1.02 
1.08 

I-I3 
1.20 

I- 13 

2.17 
2.62 
2.06 
2.38 
2.32 
2.61 
2. II 
2.II 

2.32 
2.31 
2.19 

2^39 
2.24 
1.97 
2.04 
2.06 

Average 
Neutral 

2.18 
2.05 

1.03 
1.69 

I. II 

.76 
.85 

1.06 
1. 12 

2.29 
2.37 

2.19 
2.50 

Average  of  all 

2.16 

.77 

1.07 

2.31 

2.22 

EFFECT  OF  SUGGESTION  UPON  MUSCULAR  ACTIVITY. 


589 


In  Table  IX.  we  have  a  restatement  of  Table  V.,  and  in 
Table  X.  restatement  of  Table  VI.  to  show  the  effect  respec- 
tively of  positive,  negative  and  neutral  suggestions  upon  the 
three  subjects. 

From  these  tables  it  is  evident  that  the  negative  suggestions 
tend  more  than  the  positive  suggestions  with  subject  '  W  '  to 
heighten  the  maxima,  and  this  is  especially  true  with  his  left 
hand.  But  with  the  other  two  subjects  the  positive  suggestions 
as  a  general  rule  are  superior  to  the  negative  in  this  respect. 
However  in  all  three  cases  the  negative  auto-suggestions  with 
the  left  hand  are  clearly  superior  to  the  positive  in  heightening 
the  maxima.  Why  this  is  the  case  is  difficult  to  say.  Possibly, 
the  subject  feels  that  after  audibly  declaring  that  he  can't  make 
it  as  strong  as  usual,  he  must  exert  greater  effort  in  order  to 
neutralize  the  suggestion's  effect  and  actually  obtain  his  maxi- 
mum. With  the  right  hand,  however,  this  tendency  does  not 
appear,  perhaps  because  of  the  hand's  greater  use  and  its  con- 
sequent greater  fineness  in  discrimination.     Indeed  it  appears 

Table  IX. 
Subject  'B.' 


With  the  Right  Hand. 

With  the  Left  Hand. 

Positive. 

Negative. 

Neutral. 

Positive. 

Negative. 

Neutral. 

Auditory 
Visual 
Auto. 
Neutral 

38.8 
38.9 

39-7 

38.4 
38.6 

39- 0 

39-0 

29.6 
29.9 
29-5 

28.9 

29-3 
29.9 

29.4 

Average 

39-1 

38.7 

39-0 

29.7 

29.4 

29.4 

Subject  '  J. 


Auditory 

Visual 

Auto. 

Neutral 


Average 


17.2 
17.1 
17-5 


17-3 


17.1 
17.1 
17.1 


17.1 


16.9 


16.9 


15.0 
15-0 

15-2 


15.1 


15.4 
14.8 

15-3 


15-2 


15.0 


I5-0 


Subject  'w.' 


Auditory 
Visual 
Auto. 
Neutral 

Average 


33.8 
33-5 


33-5 


33-3 
33-5 
33-6 


33-5 


33-4 
33-4 


237 
24.4 
24.2 


24.1 


234 
24.4 
25.6 


24-5 


23-5 
23-5 


290 


£DIV.    K.    STRONG. 


Table  X. 
Subject  '  B.' 


With  the  Right  Hand. 

With 

the  I,eft  Hand. 

Positive. 

Negative. 

Neutral. 

Positive. 

Negative. 

Neutral.; 

Auditory  can-can 't 
Visual  can-can't 
Auditory  +  and  — 
Visual  +  and  — 
Neutral 

40.3 
39-4 
39-6 
39-3 

39-7 
40.1 

39-4 
39-6 

39-4 

31.8 
31.0 
31.2 
31-3 

314 
31-3 
30.8 
31-3 

30.8 

Average 

39-7      1       39-7 

39-4 

31-3 

31.2 

30.8 

Subject  'J. ' 


Auditory  can-can't 
Visual  cau-cau't 
Auditory  -f  and  — 
Visual  +  and  — 
Neutral 


Average 


16.9 
16.9 
16.7 
16.9 


16.9 


16.9 
16.S 
16.7 
16.7 

16.8 


16.7 


16.7 


15.9 
16.4 
16.2 
16.3 


16.2 


16.3 

15.9 
16.1 
16.4 


16.1 


16.0 


16.0 


Subject  'W. 


Auditory  can-can't 
Visual  can-can't 
Auditory  +  and  — 
Visual  +  and  — 
Neutral 


Average 


32.8 

32.9 
32.2 

324 


32.6 


32.6 

33-2 
32.1 
32.8 


32.7 


32.2 


25-1 

25-3 
24.8 

25-3 


254 
25-3 
25.1 
25-9 


32.2 


25-1 


25-5 


24.9 


24.9 


true  that  the  so-called  maximum  effort  in  this  experiment  is  not 
a  real  maximum  exertion  each  time,  but  rather  is  an  effort  to 
attain  a  sort  of  definite  standard.  The  left  hand  is  thus  at  a 
disadvantage  in  maintaining  its  maximum,  or  definite  standard, 
because  of  its  lesser  use  and  inferior  discrimination. 

In  Tables  XI.  and  XII.  we  have  still  a  different  restatement 
of  Tables  V.  and  VI.  for  the  purpose  of  showing  the  effect  of 
particular  types  of  suggestion.  In  these  tables  the  figure  placed 
opposite  each  suggestion  is  the  average  of  that  type's  positive 
and  negative  suggestions  taken  together ;  and  the  types  are 
arranged  according  to  the  magnitudes  of  the  averages. 

We  must  conclude  from  these  tables  that :  (i)  the  auto-sug- 
gestions tend  most  strongly  of  all  the  types  of  suggestion  to 
heighten  the  maxima ;  (2)  that  during  the  first  term  the  visual 
suggestions  were  superior  in  this  respect  to  the  auditory  sugges- 
tions with  subjects  '  B  '  and  '  W,'  and  were  inferior  with  subject 


EFFECT  OF  SUGGESTION  UPON  MUSCULAR  ACTIVITY.      2C)I 

Table  XL 
With  the  Right  Hand. 


Subject '  B.' 

Subject '  J.' 

Subject 'W.' 

Auto.        39-35 
Neutral     39.0 
Visual       38.75 
Auditory  38.6 

Auto.          17.3 
Auditory  17.15 
Visual       17. 1 
Neutral     16,9 

Visual       33.65 
Auto.         33.55 
Neutral    33.4 
Auditory  33.2 

With  the;  Left  Hand. 


Auto.         29.7 

Auto.         15.25 

Auto.         24.9 

Visual       29.6 

Auditory  15.2 

Visual       24.4 

Neutral    29.4 

Neutral     15.0 

Auditory  23.55 

Auditory  29.25 

Visual       14.9 

Neutral     23.5 

Table  XII. 
With  the  Right  Hand. 


Subject '  B.' 

Subject  '  J.' 

Subject  'W.' 

Auditory  Can-Can't 

40.0 

Auditory  Can-Can't 

16.9 

Visual  Can-Can't 

33-1 

Visual  Can-Can't 

3Q.8 

Visual  Can-Can't 

16.9 

Auditory  Can-Can't 

32.7 

Auditory  +  and  — 

39-5 

Auditory  +  and  — 

16.8 

Visual  -|-  and  — 

32.6 

Visual  +  and  — 

.39-4 

Visual  +  and  — 

16.8 

Neutral 

32.2 

Neutral 

39-4 

Neutral 

16.7 

Auditory  +  and  — 

32.1 

With  the  Left  Hand. 


Auditory  Can-Can't 

31.6 

Visual  +  and  — 

16.4 

Visual  +  and  — 

25.6 

Visual  +  and  — 

31-3 

Visual  Can-Can't 

16.2 

Visual  Can-Can't 

25.3 

Visual  Can-Can't 

31.2 

Auditory  +  and  — 

16.2 

Auditory  Can-Can't 

25.2 

Auditory  -\-  and  — 

31.0 

Auditory  Can-Can't 

16.1 

Auditory  +  and  — 

25.0 

Neutral 

30.8 

Neutral 

16.0 

Neutral 

24.9 

'J,'  while  during  the  second  term  the  visual  suggestions  were 
superior  with  subject  '  W '  and  the  left  hand  of  subject  '  J',  and 
were  inferior  with  the  right  hand  of  subjects  '  B  '  and  '  J  ' ;  and 
(3)  that  during  the  second  term  the  motto  suggestions  (^.  g:, 
"  Now  you  can  make  it  stronger  than  usual  ")  were  superior 
to  the  symbol  suggestions  (^.  ^.j  plus  sign)  in  heightening  the 
maxima. 

Before  attempting  any  explanation  of  these  results  it  should 
be  borne  in  mind  that  Miss  G.  M.  Jones,  working  at  the  same 
general  problem  outlined  in  this  paper,  and  with  two  of  the  same 
subjects,  but  upon  the  reproduction  of  distance  instead  of  upon 
maximal  exertion,  obtains  the  most  accurate  reproduction  of  dis- 
tance with  the  neutral  '  suggestion,'  while  the  other  suggestions, 


292  EDW.    K.    STRONG. 

instead  of  aiding  in  the  reproduction  of  distance,  apparently 
disturb  the  accuracy  of  such  reproduction.  (It  is  notable  that 
all  three  subjects  were  affected  nearly  alike  in  her  experiftient 
while  there  were  such  different  effects  with  different  subjects  in 
my  own  experiment,  as  well  as  in  Brand's.) 

Suggestion  then  affects  the  reproduction  of  distance  by  act- 
ing as  a  disturbing  factor,  but  aids,  as  my  results  show,  when 
applied  to  maximal  muscular  effort.  From  these  two  experi- 
ments it  seems  probable  that  when  accurate  work  is  to  be  done 
all  suggestions  prevent  the  best  work  ;  but  when  mere  amount 
of  muscular  effort  is  called  for,  any  arousal  of  the  attention  to 
the  work  acts  as  a  stimulant  and  enables  the  person  to  do  better 
than  he  would  otherwise  have  done.  This  effect  is  also  shown 
by  an  incident  which  occurred  with  subject  '  W.'  Near  the 
close  of  the  series  with  his  left  hand  the  experiments  were  in- 
terrupted by  a  messenger  who  notified  him  that  he  was  awaited 
elsewhere.  The  eagerness  to  be  through  the  experiment  caused 
a  rise  of  approximately  five  kilograms,  or  eleven  pounds,  in  his 
grip  for  the  remaining  eight  trials. 

I  have  used  the  word  '  attention  '  in  this  connection  because 
I  do  not  know  a  better,  yet  I  arp  not  entirely  satisfied  that  it  is  a 
question  of  the  attention,  /.  e.,  that  it  is  an  intellectual  arousal 
that  causes  the  results  described  in  this  paper.  That  there  is  an 
arousal  of  the  whole  person  is  certain ;  but  whether  the 
heightened  maxima,  as  in  the  case  just  cited,  are  due  to  the 
attention  directly  or  to  an  indirect  effect  of  the  general  stir,  it 
is  difficult  to  be  certain.  I  do  not  feel  that  it  is  a  question  of 
the  will  primarily,  for  that  factor  is  supposed  to  be  eliminated 
from  the  experiment  by  the  instruction  at  the  commencement 
of  work,  when  the  subject  was  told  to  make  his  maximum 
effort  each  time. 

Yet  with  these  misgivings,  it  seems  natural  to  explain  the 
greater  efficacy  of  the  auto-suggestions  by  a  greater  concentra- 
tion of  the  attention  upon  the  work  in  hand.  An  auto-sugges- 
tion consisted  of  the  statement  by  the  conductor  of  the  experi- 
ment, "Now  you  can  make  a  suggestion  of  your  own  ";  this 
was  followed  by  the  statement  of  the  subject,  "  Now  I  can  make 
it  stronger  than  usual"  or  "  Now  I  can't  make  it  as  strong  as 


EFFECT  OF  SUGGESTION   UPON  MUSCULAR  ACTIVITY.      293 

usual."  The  whole  process  tended  to  call  forth  greater  con- 
centration of  attention  to  the  next  grip  of  the  dynamometer  than 
would  result  from  either  the  auditory  or  visual  suggestion,  where 
there  was  only  an  act  on  the  part  of  the  conductor. 

On  the  other  hand  a  certain  broad  arousal  perhaps  accounts 
for  the  marked  superiority  of  the  motto  suggestions,  "Now 
you  can  make  it  stronger  than  usual  "  and  "  Now  you  can't 
make  it  as  strong  as  usual "  over  the  symbol  suggestions,  '  +  ' 
and  '  — .'  The  latter,  especially  when  spoken  ('auditory  sug- 
gestion ')  occupied  but  a  moment  and  did  not  arouse  the  subject 
as  did  the  motto-suggestions,  for  the  latter  required  a  greater 
length  of  time  to  be  understood. 

Introspections  of  all  three  subjects  were  in  general  that  the 
suggestions  had  little  effect  upon  them.  For  example  at  the 
end  of  the  second  term  subject  '  B  '  once  stated  that  the  auditory 
suggestion  '  can '  seemed  perhaps  most  powerful  and  the  visual 
suggestion  (  +  )  was  next,  but  that  it  did  not  seem  as  if  any 
were  strong  enough  to  produce  an  effect.  And  about  the  same 
time  subject  'J'  stated  her  feeling  as  follows,  "  When  I  stop  to 
think  the  suggestion  seems  to  have  little  effect,  but  when  not 
thinking  I  feel  that  I  obey  the  suggestion."  Throughout  the 
experiment  notes  were  taken  of  those  cases  in  which  the  subject 
expressed  himself  as  satisfied  or  dissatisfied  with  the  result.  A 
careful  analysis  of  these  fails  to  show  any  correlation  between 
the  actual  result  and  the  introspections. 


lli)teit|  of  Caiifofnia 

Psychological  laboratoi). 


[Reprinted  from  The  Psychological  Review,  Vol.  XVII.,  No.  4,  July,  1910.] 


XIII.     The  Localization  of  Diasclerotic  Light. 

BY  G.  M.  STRATTON. 

Sometime  agoVeraguth^  announced  that  the  sensation  pro- 
duced by  stimulating  the  retina  through  the  sclerotic  coat  instead 
of  through  the  pupil  is  often  localized  upon  the  same  side  as 
that  upon  which  the  stimulus  falls,  and  that  this  is  particularly 
true  when  the  stimulus  falls  upon  the  temporal  side.  With 
some  persons,  however,  he  found  that  under  these  circumstances 
there  was,  in  addition  to  the  sensation  on  the  temporal  side,  a 
weaker  sensation  localized  upon  the  nasal  side.  On  the  other 
hand,  when  the  stimulus  was  applied  to  the  nasal  side  the  sensa- 
tion was  always  localized  in  the  normal  way,  that  is,  it  was 
referred  to  the  temporal  side.  When  the  light  was  applied  to 
the  sclerotic,  not  in  a  radial,  or  diametric,  direction,  but  in  a 
direction  approximating  that  of  the  tangent  at  that  point,  no 
change  was  noticed  in  the  place  the  light  seemed  to  occupy  in 
the  visual  field.  From  this  fact  Veraguth  argues  against  the 
assumption  that  the  light,  when  it  falls  upon  the  temporal  side 
of  the  sclerotic,  passes  through  and  strikes  the  retina  upon  the 
nasal  side  and  therefore  is  referred  in  quite  normal  fashion  to 
the  side  opposite  to  that  upon  which  it  really  affects  the  retina. 
He  believes  that  we  have  here  an  indubitable  departure  from 
the  common  cross-localization  of  visual  impressions,  and  would 
explain  this  departure  by  the  biological  principle  of  utility.  As 
regards  the  need  of  a  correct  localization  of  light  penetrating 
the  sclerotic,  there  is,  he  feels,  a  great  difference  between  the 
temporal  side  of  the  eye  which  is  open  and  exposed,  and  the 
inner  or  nasal  side  which  is  screened  by  the  nose.  And  he 
maintains  that  the  correct  orientation  of  light  coming  diasclerot- 
ically  is  important  only  when  the  light  falls  on  the  temporal 
side ;  on  the  nasal  side  the  light  would  come  not  only  through 
the  sclerotic  coat,  but  through  the  pupil,  and  therefore  would 

^ '  Die  Verlegung  diaskleral  in  das  menschliche  Auge  einfallender  Licht- 
reize  in  den  Raum,'  Zeitschrift  fur  Psychologic,  Vol.  42,  pp.  162  fif. 
294 


Onlwfsitj  of  California 

pi  iBboratory. 


295  G.    M.    STRATTON. 

be  localized  correctly  according  to  the  well-known  law.  Pres- 
sure phosphenes,  unlike  many  of  these  sensations  produced  by 
diasclerotic  stimulation,  are  all  projected,  he  finds,  to  the  oppo- 
site side  of  the  visual  field  ;  and  this  to  him  seems  reasonable, 
because  there  is  no  advantage  in  their  being  projected  other- 
wise. They  therefore  follow  the  general  law  for  the  projection 
of  a  stimulus  which  comes  through  the  pupil. 

Veraguth  believes  that  the  present  phenomena  are  a  stum- 
bling block  in  the  way  of  the  nativistic  theory  of  vision  which 
supposes  that  the  space  value  of  the  impression  inheres  in  the 
retinal  element.  For,  if  this  were  the  case,  why  should  there 
be  a  difference  between  the  localization  of  the  sensation  re- 
sulting from  the  diasclerotic  stimulation  and  that  from  the  dia- 
pupillary?  But  the  empiristic  theory,  he  argues,  can  well 
admit  and  explain  these  diverse  facts,  for  it  supposes  that 
localization  is  due  to  a  complex  of  factors,  of  which  the  retinal 
factor  is  but  one.  Now  the  diasclerotic  and  the  diapupillary 
stimulation,  he  holds,  may  each  arouse  a  different  group  of 
factors  to  determine  its  localization.  Each  may  well  be  con- 
nected, for  example,  with  a  different  group  of  muscular  re- 
sponses, and  therefore,  according  to  the  empiristic  view,  have 
a  different  localization.  With  some  persons  it  is  not  improbable 
that  both  the  complex  of  factors  concerned  in  diasclerotic  locali- 
zation and  the  complex  concerned  in  diapupillary  localization 
may  come  into  play  simultaneously,  and  thus  there  be  brought 
to  pass  by  diasclerotic  stimulation  a  localization  at  once  on  both 
sides  of  the  visual  field.  Thus  he  would  explain  the  double 
projection  which  was  sometimes  noticed  in  his  experiments. 

To  control  Veraguth's  data  and  explanation  a  number  of  ex- 
periments were  tried  by  the  present  writer,  at  first  by  means  of  a 
very  strong  beam  of  artificial  light  in  a  dark-room  and  brought  to 
a  point  on  the  sclerotic  coat  by  means  of  a  system  of  screens  and 
lenses.  Afterwards,  a  device  essentially  the  same  as  that  em- 
ployed by  Veraguth  himself^  was  adopted.  It  consisted  of  a 
portable  flash-light  so  covered  at  the  end  that  the  light  was  emit- 
ted only  from  a  circular  area  less  than  one  millimeter  in  diameter. 

^Veraguth,  "  Zur  Priifung  der  lyichtreaction  der  Pupillen,'  Neurologisches 
Centmlblatt  (16  April,  1905),  XXIV.  Jahrg.,  33Si:f. 


LOCALIZATION  OF  DIASCLEROTIC  LIGHT.  296 

This  small  opening  lying  well  forward  and  beyond  the  body  of 
the  lamp  could  be  brought  close  to  the  sclerotic  coat  of  the  eye, 
yet  without  actual  contact.  In  this  way  the  disturbing  sensations, 
as  well  as  the  reflexes  so  difficult  to  suppress,  were  avoided. 
The  observations  were  made  by  four  persons ;  by  two  of  these 
during  frequent  repetitions  of  the  experiment  over  a  consider- 
able stretch  of  time.  In  general,  these  experiments  while  con- 
firming much  that  Veraguth  himself  reports,  yet  bring  some 
modification  and  supplement  of  his  data,  and  lead,  I  venture  to 
suggest,  to  a  different  conclusion. 

There  are  regions  upon  the  temporal  side  where  the  light  is 
lo'calized  in  the  normal  way ;  that  is,  upon  the  nasal  side. 
There  are  regions  where  the  light  is  localized  entirely  upon  the 
temporal  side.  There  is  often  found  also  a  zone  where  there  is 
some  kind  of  localization  upon  both  sides  at  once.  The  relation 
of  these  zones  to  one  another  is  as  follows  :  The  region  where 
the  sensations  are  localized  on  the  same  side  begins  immediately 
posterior  to  the  outer  edge  of  the  iris  and  extends  backward 
a  distance  nearly  equal  to  the  distance  from  the  center  of  the 
pupil  to  the  outer  edge  of  the  iris.  The  region  where  the  lo- 
calization is  upon  the  opposite  side  is  still  farther  back.  The 
region  of  double  localization  lies  at  the  junction,  or  between  the 
borders,  of  these  two  zones. 

Upon  the  nasal  side  of  the  eye  my  own  observations  confirm, 
but  not  entirely,  those  of  Veraguth.  The  localization  is  now 
far  more  frequently  upon  the  side  opposite  to  that  upon  which 
the  stimulus  falls,  than  in  the  case  of  temporal  stimulation 
through  the  sclerotic  coat.  Yet  occasionally  there  are  found 
localities  well  forward  where  the  sensation  is  localized  upon  the 
same  side  as  the  stimulus. 

The  localization  of  pressure  phosphenes  shows  this  pecu- 
liarity :  that  the  phosphenes,  so  far  as  I  can  observe,  are  obtain- 
able only  upon  those  regions  of  the  eye  where  light  stimulus, 
passing  through  the  sclerotic  coat,  arouses  what  I  should  call  a 
more  definite,  a  more  figurate  or  punctiform  sensation.  In  the 
anterior  region  where  the  application  of  light  upon  the  sclerotic 
gives  a  vague  sensation  of  light,  local  pressure  upon  the  scle- 
rotic coat  produces  no  phosphenes  whatever.     The  phosphenes. 


297  G.    M.    STRATTON. 

however,  when  produced,  are  always  localized  upon  the  side 
opposite  to  that  of  the  incidence  of  the  stimulus,  as  Veraguth 
himself  observed.  By  test  experiments  in  which  there  was 
carefully  noted  the  angle  in  the  visual  field  where  the  extreme 
outlying  phosphenes  are  localized,  I  find  them  ceasing  to  appear 
at  about  the  outmost  limit  for  the  perception  of  light  coming 
through  the  pupil.  This  would  tend  to  confirm  one  in  the  be- 
lief that  the  retinal  limit  for  response  to  actual  light  is  the  same 
as  that  for  pressure  stimulation. 

Veraguth  has  laid  considerable  emphasis  upon  the  fact  that 
no  change  in  the  localization  of  the  sensation  takes  place  when, 
instead  of  having  the  stimulus  come  to  the  outer  coat  of  the  eye 
in  a  diametric  direction,  it  is  introduced  in  a  direction  approxi- 
mately that  of  the  tangent  at  that  point.  It  does  not  seem,  how- 
ever, that  this  fact  should  be  regarded  as  of  great  importance. 
It  would  be  of  importance  were  the  outer  coats  of  the  eye 
perfectly  transparent ;  but  the  sclerotic,  being  translucent, 
would  in  any  event  diffuse  the  light  much  as  would  tissue-paper 
or  egg-shell ;  that  is  to  say,  the  light  would  be  transmitted  in 
all  directions  from  the  point  of  incidence  more  or  less  indiffer- 
ently, whether  the  light  itself,  in  arriving  at  that  point,  came  in 
one  direction  or  another.  In  consequence,  we  should  expect 
that  if  the  sensation  itself  were  in  anywise  due  to  the  passage 
of  light  into  the  bulb  of  the  eye,  and  over  to  the  retina  upon  the 
opposite  side,  it  would  not  be  affected  by  a  change  from  dia- 
metric to  tangential  incidence. 

Another  fact  which  must  be  taken  into  account  in  the  ex- 
planation of  the  experimental  data  is  that  there  is  a  retinal  zone 
of  considerable  width  anterior  to  the  07'a  scrrata  which  contains 
neither  rods  nor  cones. ^  Yet  this  is  a  region  where  light,  falling 
upon  the  sclerotic  coat,  nevertheless  produces  light  sensations. 
And,  furthermore,  the  present  experiments  lead  me  to  believe  that 
this  is  the  region  especially  liable  to  the  production  of  the  dif- 
fused sensations  which  are  localized  upon  the  temporal  side, 
both  by  temporal  and  by  nasal  stimulation.      It  would  seem,  to 

^See  Piersol,  Human  Anatomy,  1907,  pp.  1456,  1467  ;  Tolot,  Anatomischer 
Atlas,  1907,  p.  892  ;  Werner  Spalteholtz,  Hand  Atlas  of  Human  Afiatomy,  tr. 
Barker,  III.,  772,  780;  Huber,  Text-book  of  Histology,  tr.  Gushing,  1900,  p. 
422.     I  am  indebted  to  my  colleague,  Dr.  Moody,  for  assistance  upoq,this  point. 


LOCALIZATION  OF  DIASCLEROTIC  LIGHT.  298 

express  it  mildly,  anomalous  to  explain  the  localization  of  light 
here  as  though  there  were  actual  light-sensitive  elements 
directly  beneath  the  region  of  the  sclerotic  where  the  stimulus 
falls. 

There  is,  one  must  confess,  some  difficulty  at  the  present 
time  in  giving  any  explanation  of  all  the  facts  which  appear  in 
this  interesting  experiment.  Yet  on  the  whole  there  would 
seem  sufficient  reason  to  believe  that  Veraguth's  theory  is  forced 
and  improbable. 

In  the  first  place,  it  is  hardly  in  keeping  with  other  well- 
known  facts  of  retinal  behavior  to  suppose  that  the  stimulation 
of  the  very  same  retinal  elements  will  lead  to  such  different 
localization  by  reason  of  some  change  in  the  manner  of 
a^p'oach  to  those  elements.  The  stimulation  of  the  rods  and 
cones  by  pressure,  for  example,  —  a  stimulation  which  also 
comes  through  the  sclerotic,  and  consequently  by  a  course 
entirely  different  from  that  of  ordinary  photic  stimulation  — 
occasions  no  upset  of  the  normal  localization  of  these  elements ; 
their  sensation  is  referred  to  exactly  the  same  place  as  though 
it  were  caused  by  light,  and  had  come  through  the  pupil. 

The  facts  perhaps  are  better  explained  by  assuming  that  the 
light  which  penetrates  the  sclerotic  coat  posterior  to  the  ora  ser- 
rata  and  which  consequently  excites  the  light-sensitive  elements 
of  the  retina  directly  beneath  or  adjacent  produces  the  definite  or 
figurate  sensation  which  is  localized  upon  the  opposite  side. 
This  is  the  region  where  the  localization  of  phosphenes  and  that 
of  sensations  produced  by  light  stimulus  are  identical.  But 
where  the  light  falls  anterior  to  the  ora  serrata  it  of  course  can- 
not reach  immediately  and  upon  the  same  side  of  the  eye  light- 
sensitive  elements  but  can  stimulate  them  only  after  first  being 
diffused  through  the  interior  of  the  bulb.  The  character  of 
this  diffusion  will  be  such  that  the  light  will  pass  in  straight 
lines  from  its  point  of  incidence  upon  the  sclerotic,  but  in  lines 
traversing  the  interior  of  the  bulb  in  all  directions  and  not 
just  in  the  direction  which  is  a  continuation  of  that  along  which 
it  was  travelling  before  its  incidence.  The  behavior  of  the 
light  here  is  such  as  one  would  get  in  a  dark  room  if  a  beam  of 
light  fell   upon   a  plate  of  ground-glass  in  an  aperture  of  the 


299  ^-    ^^-    STRATTON. 

wall.  There  would  be  a  general  illumination  of  the  room  but 
naturally  more  intense  upon  the  side  opposite  to  the  illuminated 
spot,  yet  diffused  and  unfigurate  upon  that  side. 

This  would  account  for  two  facts  :  namely,  that  the  sensa- 
tion in  the  case  of  such  light  stimulation  as  falls  very  far  forward 
on  the  sclerotic  is  exceedingly  indefinite,  and  is  localized  upon 
the  same  side  as  that  upon  which  the  light  itself  has  been  intro- 
duced into  the  eye.  Furthermore,  it  would  account  for  the 
fact,  already  referred. to,  that  a  change  in  the  direction  along 
which  the  light  falls  upon  the  sclerotic  does  not  alter  the  char- 
acter of  the  projection,  provided  the  point  of  incidence  remain 
unchanged.  The  position  of  greatest  illumination  in  our  dark- 
room would  not  be  altered  perceptibly  by  altering  the  direction 
along  which  the  light  proceeded  to  the  plate  of  ground-glass. 

The  behavior  of  the  sensation  produced  by  light  falling  on 
the  nasal  side  one  must  confess  is  mildly  puzzling.  For  the 
most  part  all  stimuli  here,  no  matter  how  far  forward  they  fall, 
are  referred  to  the  opposite  side  ;  yet  we  should  expect  that  if 
we  go  forward  of  the  ora  serraia  on  this  side  we  should  find 
that  the  sensations  were  referred  exclusively  to  the  nasal  side. 
The  facts  here  obtained  may  perhaps  be  accounted  for  by  the 
fact  that  the  ora  serrata  upon  this  side  reaches  farther  forward  ^ 
than  upon  the  opposite  side,  in  accord  with  the  familiar  obser- 
vation that  the  field  of  view  upon  the  temporal  side  is  always 
wider  than  upon  the  nasal.  Consequently  the  stimulus  intro- 
duced diasclerotically  upon  the  nasal  side  would  almost  inevi- 
tably find  light-sensitive  elements  adjacent  to,  if  not  directly 
beneath,  the  point  of  incidence;  and  the  sensation  thereby  pro- 
duced would  by  its  intensity  quite  drown  any  sensation  arising  from 
a  diffusion  inside  the  eye.  It  is  possible  also  that  this  phenome- 
non of  irregular  localization  is  to  some  extent  occasioned  by  a 
reflection  of  light  from  the  surface  of  the  crystalline  lens  per- 
haps near  its  periphery.  This  surface  of  the  lens  might  easily 
reflect  the  light  back  to  the  same  side  as  that  upon  which  it 
entered  the  sclerotic,  though  to  a  point  somewhat  farther  back. 
Thus  it  would  reach  the  sensitive  portions  of  the  retina  and  now 
quite  normally  be  localized  upon  the  opposite  side. 

^See,  e.  g.,  Werner  Spalteholtz,  op.  cit.,  III.,  p.  780. 


LOCALIZATION   OF  DIASCLEROTIC  LIGHT.  300 

All  cases  where  there  is  a  double  localization  from  a  single 
stimulation,  that  is  to  say,  a  localization  at  once  upon  both 
sides  of  the  visual  field,  could  well  be  accounted  for  by  sup- 
posing that  the  light,  after  passing  through  the  sclerotic,  reaches 
not  solely  those  light-sensitive  elements  which  lie  in  the  portions 
of  the  retina  immediately  beneath  or  adjacent,  but  is  also  dif- 
fused to  the  opposite  side  of  the  inner  chamber  and  there  falling 
diffusely  upon  the  retina  is  referred  to  the  side  opposite  to  that 
upon  which  the  more  definite  sensation  is  localized.  We  should 
thus  have  two  spacially  disjoined  sensations  occurring  from  a 
single  impression  because  the  stimulus  actually  fell  upon  dis- 
joined portions  of  the  retina. 

My  own  feeling  therefore  is  that  nothing  appears  in  these 
experiments  with  diasclerotic  light  which  is  at  all  discordant 
with  the  law  governing  the  localization  of  diapupillary  impres- 
sions. Visual  localization  is  based  upon  the  positions  which 
objects  normally  occupy  when  stimulating  the  different  points 
of  the  retina;  and  this  localization,  once  established,  takes 
no  account  whatever  of  the  course  by  which  the  stimulus 
happens  actually  to  arrive.  No  questions  are  asked  as  to 
whether  it  has  entered  by  the  door  or  has  broken  in  as  a  thief 
and  a  robber;  it  is  treated  in  all  cases  psychically  alike. 


llnlYcrsltf  of  California 

Psychological  Laboratory. 


FROM  THE   UNIVERSITY  OF   CALIFORNIA 
PSYCHOLOGICAL   LABORATORY 

XIV.   The  Psychology  of  Change:   on  Some  Phases 
OF  Minimal  Time  by  Sight 


BY  JOHN  M.   BREWER,  B.S. 


Repiinted  from  the  Psychoi^ogicai,  Review,  July,  191 1, 
Vol.  XVIII,  No.  4. 


""'tfsffy  «f  California 


[Reprinted  from  The  Psychological  Review,  Vol.  XVIII.,  No.  4,  July,  1911.] 


FROM  THE  UNIVERSITY  OF   CALIFORNIA 
PSYCHOLOGICAL   LABORATORY 

XIV.   The  Psychology  of  Change:   on  Some  Phases 
OF  Minimal  Time  by  Sight 

BY  JOHN  M.  BREWER,   B.S. 

The  present  paper  is  concerned  with  the  description  of  an 
experiment  that  attempts  to  bring  nearer  the  answer  to  the 
following  questions:  (i)  What  is  the  smallest  time-interval 
between  two  successive  lights  when  the  lights  are  seen  to 
come  not  simultaneously  but  in  succession?  (2)  What  is 
the  smallest  extent  of  time  that  a  motion  can  last,  and  still 
be  perceived  as  motion?  And  the  investigation  of  these  two 
questions,  with  the  hope  of  bringing  out  some  connection  or 
disconnection  of  the  one  group  of  facts  with  the  other,  was 
confined  to  a  special  set  of  conditions;  namely,  that  in  which 
the  two  points  whose  succession  or  simultaneity  Is  to  be 
observed,  are  not  in  absolute  juxtaposition  but  are  appreciably 
apart,  and  where  the  space-interval  between  them  Is  varied 
as  we  pass  from  group  to  group  of  experiments.  For  It 
seemed  an  open  question  whether  an  advantage  that  might 
accrue,  let  us  say,  to  either  motion  or  succession,  when  one 
space-interval  was  involved,  would  also  be  maintained  with 
a  different  Interval  of  space. 

The  subject,  in  a  somewhat  darkened  room,  was  placed 
360  cm.  distant  from  a  large  screen  bearing  a  narrow  vertical 
slit  that  could,  for  the  sake  of  proper  fixation,  be  dimly  seen. 
And  In  this  position  he  saw  either  two  lights  in  succession, 
one  directly  above  the  other,  or  else  a  moving  point  of  light. 
These  were  produced  In  the  following  way.  Behind  the 
screen  and  directly  in  line  with  the  slit  was  a  surface  evenly 
lighted  by  an  electric  light;  and  between  screen  and  lighted 
surface  swung  a  pendulum,  bearing  a  wide  sheet  of  metal, 
set  Into  w^hlch  were  devices  for  producing  the  appearances 

257 


25S  JOHN  M.  BREWER 

described  above.  For  giving  an  appearance  of  succession 
two  small  apertures  were  cut  in  separate  slides  that  were  in 
reality  circular  arcs  so  arranged  that  the  apertures  would 
pass  the  slit  with  a  varying  intervening  time,  yet  with  no 
varying  of  their  distance  from  the  point  of  suspension  of  the 
pendulum;  and  consequently  for  any  given  set  of  experiments 
they  presented  to  the  observer  always  the  same  angular,  or 
vertical,  separation.  Yet  in  the  different  sets  of  experiments 
the  amount  of  their  vertical  separation  differed,  being  respec- 
tively 7,  10  and  19.5  mm.,  or,  expressed  in  angular  measure, 
6.7',  9.5'  and  18.6'  of  arc. 

Instead  of  the  appearance  of  succession,  it  was  possible 
to  offer  an  appearance  of  motion  by  substituting  for  the 
apertures  just  described  a  circular  card  that  could  be  moved 
at  will  about  its  own  center.  In  this  circular  card  there  was 
a  narrow  slit;  and  by  different  settings  of  the  card  its  slit 
could  be  placed  at  any  angle  to  the  slit  in  the  stationary 
screen  immediately  before  it;  and  consequently  there  was 
presented  to  the  observer  the  appearance  of  a  point  of  light 
moving  either  up  or  down.  The  extent  of  the  motion  up 
and  down  was  carefully  limited  by  opaque  surfaces  above 
and  below,  and  made  to  correspond,  in  the  three  parts  of  the 
experiment,  with  the  spatial  angles  above  mentioned:  6.7', 
9.5'  and  18.6'.  The  velocity  of  the  apparent  movement, 
of  course,  varied  step  by  step  with  the  shifts  in  the  angle  of 
the  pendulum  slit.  The  swing  of  the  pendulum  was  kept 
constant  by  the  use  of  magnets,  and  its  speed  in  the  vicinity 
of  the  center  was  carefully  calibrated  by  means  of  a  tuning- 
fork. 

In  determining  the  thresholds  for  the  different  orders  of 
stimulation,  the  method  of  serial  groups^  was  used,  'no- 
interval'  cases  being  intermixed  about  equally  with  the  inter- 
vals whose  thresholds  were  sought.  The  threshold  was 
crossed  after  the  manner  of  the  method  of  minimal  changes, 
and  for  both  orders  of  sequence  (viz.,  upper  light  first,  and 
lower  light  first),  and  of  motion  (viz.,  downward  and  upward). 
Each   value   in   Tables    I.-III.    is   then    an   average   of   four 

1  See  '  Studies  from  the  Univ.  of  Calif.  Lab.,  IV.,'  Psychol.  Review,  IX.,  1902,  444. 


MINIMAL  TIME  BY  SIGHT 


259 


'determinations'  and  into  each  determination  there  enter 
forty  to  fifty  experiments.  And  since  it  was  often  the  case 
that  an  observer  could  tell  that  the  lights  came  at  different 
times,  but  could  not  tell  which  came  first,  or  observed  motion, 
though  he  could  not  tell  its  direction,  the  two  kinds  of 
threshold  are  here  recorded  separately — the  threshold  for  the 

Table  I 

Thresholds,  Expressed  in  ff,  for  Visual  Angle  6.7' 


With  Discrete  Sequence. 

with  Motion. 

Observer. 

Judg.  of  Succes- 
sion Merely. 

Judg.  of  Order  of 
Succession. 

Judg.  of  Motion 
Merely. 

Judg.  of  Direction 
of  Motion. 

B 

L 

M 

S 

W 

22 
22 

54 

20 

33 

29 
22 
60 

22 

43 

29 
21 
48 
30 

22 

31 
21 
48 
32 
30 

Table  II 

Thresholds,  Expressed  in  <r,  for  Visual  Angle  9.5' 


With  Discrete  Sequence. 

With  Motion. 

Observer. 

Judg.  of  Succes- 
sion Merely. 

Judg.  of  Order  of 
Succession 

Judg.  of  Motion 
Merely. 

Judg.  of  Direction 
of  Motion. 

B 

L 

M 

S 

W 

22 
32 
58 

35 
33 

30 
32 
61 

35 
33 

22 

33 
28 
21 

22 
19 

33 
32 
21 

Table  III 


Thresholds,  Expressed  in  c,  for 

Visual  Angle  18.6' 

With  Discrete  Sequence. 

With  Motion. 

Observer. 

Judg.  of  Succes- 
sion Merely. 

Judg.  of  Order  of 
Succession. 

Judg.  of  Motion 
Merely. 

Judg.  of  Direction 
of  Motion. 

B 
L 

M 

S 

W 

37 
28 

S3 

45 
43 

39 
30 
60 

45 
52 

30 
20 
76 
24 
20 

30 
20 
76 

24 
20 

bare  perception  of  the  succession  or  motion,  and  that  for  the 
definite  order  of  the  succession  or  for  the  direction  of  motion. 
It  should  be  said  that  the  subjective  appearance  of  motion, 
which    Exner    noticed,    did    not    appear   to    any    important 


36o 


JOHN  M.  BREJVER 


extent  in  making  these  determinations.  Only  one  subject 
had  this  illusion,  and  he  for  a  very  short  time  only.  The 
results  are  stated  in  thousandths  of  a  second. 

There  is  in  many  cases,  as  these  tables  show,  a  lower 
threshold  when  motion  is  offered  than  when  there  is  offered 
discrete  sequence.  In  the  thirty  pairs  of  values  that  are 
comparable  in  this  respect,  twenty-one  show  a  clear  advantage 
for  motion.  Yet  in  none  of  these  pairs  is  there  any  such 
advantage  as  Exner  noted.  Moreover,  it  is  evident  that  the 
smallest  visual  angle  is  for  the  greater  number  of  the  observers 
the  most  favorable  of  the  three  for  the  perception  of  the 
discrete  sequence,  whether  the  judgment  passed  be  of  sequence 
merely  or  be  of  the  order  of  the  sequence.  The  separation 
of  the  lights  would  here  seem  to  be  sufficient  to  prevent  at 
least  any  troublesome  degree  of  overlapping  of  the  irradiation 
circles  upon  the  retina,  and  at  the  same  time  not  so  great  as 
to  render  comparison  difficult.  At  the  angle  9.5',  such  com- 
parison seems  already  to  have  become  harder  and  at  18.6' 
harder  still.  For  the  perception  of  motion,  however,  the 
most  favorable  space  extent  for  most  of  the  observers  was 
neither  the  shortest  nor  yet  the  longest  of  the  three  employed, 
but  the  middle  distance.  Motion  through  the  angle  6.7' 
seems  to  have  been  too  short  to  be  most  readily  seen  as 
motion;  while  with  the  angle  18.6'  there  evidently  was  again 
some  difficulty,  though  of  a  different  kind  and  greater — that 
again  prevented  the  distance  from  being  optimal. 

Some  idea  of  the  comparative  advantages  of  the  different 
angular  extents  may  be  gained  from  the  following  table  where- 
in the  thresholds  for  the  different  orders  of  perception  are 
stated  in  the  form  of  averages  of  the  time  obtained  for  all 
five  of  the  observers. 

Table  IV 

Average  Thresholds,  Expressed  in  <t,  for  the  Three  Visual  Angles 


Visual  Angle  6.7'. 

Visual  Angle  9.5'. 

Visual  Angle  18.6'. 

Character  of  Change 
Presented. 

Judg.  of 
Occur- 
rence 

Merely. 

Judg.  of 
Order  or 
Direction 
of  Occur- 
rence. 

Judg.  of 
Occur- 
rence 
Merely. 

Judg.  of 
Order  or 
Direction 
of  Occur- 
rence. 

Judg.  of 
Occur- 
rence 

Merely. 

Judg.  of 
Order  or 
Direction 
of  Occur- 
recne. 

Discrete  sequence 
Actual  motion 

30 
30 

35 

32 

36 

25 

38 
26 

41 

34 

45 
34 

PERCEPTION  OF  MOVEMENT  261 

So  far  as  discrete  sequence  is  concerned,  there  are,  how- 
ever, exceptional  observers,  like  M,  who  reveal  no  great 
difference  as  we  pass  from  one  visual  angle  to  another;  or, 
like  B  and  W,  for  whom  6.7'  and  9.5'  are  practically  alike, 
while  18.6'  shows  a  distinct  disadvantage.  And,  again,  in 
the  region  of  motion,  the  general  advantage  possessed  by  the 
medium  extent  9.5'  practically  disappears  with  the  observer 
W  for  whom  there  is,  if  anything,  a  very  slight  drop  in  the 
thresholds  as  we  pass  out  to  the  very  largest  angle,  that  of 
18.6';  and  with  another  observer,  S,  this  same  tendency  is 
even  more  clear,  and  the  longest  distance,  18.6',  is  now  the 
most  favorable  of  all.  Yet  the  departure  of  these  observers 
from  the  precise  relations  found  with  their  fellows  permits 
one  still  to  say  that  there  is  in  general  in  shorter  space-extents 
a  condition  favorable  to  the  perception  of  discrete  sequence, 
and  yet  unfavorable  to  the  perception  of  motion.  And  while 
the  most  favorable  extent  here  used  for  perceiving  discrete 
sequence  gives,  on  the  average,  a  minimal  threshold  of  300-, 
the  most  favorable  extent  for  perceiving  motion  gives  a 
threshold  of  250-;  the  threshold  for  the  perception  of  discrete 
sequence  is  thus  about  one  fifth  higher  than  that  for 
motion.  This,  however,  shows  that  at  least  under  the  peculiar 
conditions  of  the  present  experiment,  there  is  a  considerable 
departure  from  the  relation  which  Exner  believed  to  exist, 
namely,  that  the  time-threshold  for  the  perception  of  succes- 
sion is  about  three  times  as  high  as  that  for  the  perception  of 
motion. 


Unlwtilt^  of  Califsrala 


FROM  THE   UNIVERSITY  OF   CALIFORNIA 
PSYCHOLOGICAL  LABORATORY 

XV.     THE    PSYCHOLOGY    OF    CHANGE:     HOW   IS  THE 

PERCEPTION  OF  MOVEMENT  RELATED  TO 

THAT  OF  SUCCESSION? 


BY   G.    M.   STRATTON 


Repiinted  from  the  Psychological  Review,  July,  1911, 
Vol.  XVIII,  No.  4. 


Mm^  t)^  California 

PsyGtioiogiGal  Laboratoi). 


XV.     THE    PSYCHOLOGY    OF   CHANGE:    HOW   IS  THE 

PERCEPTION  OF  MOVEMENT  RELATED  TO 

THAT  OF  SUCCESSION? 


BY  G.    M.   STRATTON 


Um^  nf  ilellfofnia 

Psycbologjcai  Laboratory. 


[Reprinted  from  The  Psychological  Review,  Vol.  XVIII.,  No.  4,  July,  191  i-l 


XV.  The  Psychology  of  Change:  How  is  the  Perception 
OF  Movement  Related  to  that  of  Succession? 

BY  G.  M.   STRATTON 

The  experiments  to  be  described  deal  with  a  narrow 
margin  of  that  wide  process  by  which  we  are  conscious  of 
change.  For  even  with  all  the  interest  that  has  in  past 
years  been  shown  in  this  complex  act,  one  can  hardly 
say  that  there  is  as  yet  any  general  agreement  as  to  its  inner 
character  or  as  to  its  outer  connections.  It  has  repeatedly 
been  asserted  that  change  is,  at  its  best,  caught  by  us 
directly  and  simply;  that  when  we  notice  some  sudden 
brightening  of  a  light  or  damping  of  a  sound  or  increase  of 
pain  or  shift  of  place,  the  change-experience  itself  is  of  a 
unique  quality,  like  the  taste  of  bitter  or  the  sight  of  blue, 
and  that  at  such  times  the  process  has  all  the  marks  of  a 
sensation.  The  detection  of  change,  it  is  held,  involves  at 
such  times  no  comparison,  no  overspanning  consciousness 
that  now  the  object  is  in  one  state  or  condition  and  now  in 
another,  but  we  become  aware  of  the  change  in  a  single  and 
simple  throb  of  mind.     And  all  this  has  been  denied. 

In  the  case  of  visual  movement,  to  be  more  specific — for 
with  visual  movement  alone  the  present  experiments  are  con- 
cerned— orthodox  belief  has  been  that  there  is  always  present 
a  double  act  of  discrimination,  at  once  of  instants  and  of 
positions;  against  which  is  the  belief  that  the  retina  is  directly 
responsive  to  rapid  movements  of  light,  and  that  the  move- 
ment is  perceived  without  any  such  complex  dealing  at  once 
with  space  and  time.  The  idea  of  an  absolutely  direct  and 
simple  sensory  appreciation  of  motion  suggested  by  Czermak^ 
and  to  some  extent  furthered  by  Vierordt,-  found  a  strong 

1  'Ideen  zu  einer  Lehre  von  Zeitsinn,'  Sitzungsb.  d.  kaiserl.  Akad.  d.  zviss.  Math.- 
Naturwiss.  CI,  Vol.  24  (Vienna,  1857),  pp.  231-236. 

2 'Der  Zeitsinn  nachVersuchen,'  1868;  cf.  especially  pp.  114  f.,  where  Vierordt  says 
that  in  perceiving  motion  both  the  time-sense  and  the  space-sense  are  required, 
but  that  the  processes  involving  space  and  time  cease  to  arise  clearly  in  conscious- 
ness because  they  run  so  smoothly  and  habit-like,  and  so  the  whole  takes  on  a 
quasi-sensory  character.  Accordingly,  says  he,  we  may  as  justly  use  the  expression 
Ceschwindigkehsempfindungen  as  Zeit-  und  Raumgrossenempfindungen. 
263 


PERCEPTION  OF  MOVEMENT  263 

supporter  in  Exner,  whose  argument  rests  upon  two  kinds 
of  experimental  observation,  in  the  region  of  space  and  of 
time  respectively.  In  regard  to  space,  rapid  motion  can  be 
discerned,  he  held,  within  limits  too  narrow  for  space-dis- 
crimination; a  small  disk  of  light  can  be  seen  to  move  even 
when  its  excursion  is  considerably  less  than  the  distance  be- 
tween two  such  disks  of  light  that,  when  stationary,  already 
appear  as  one.  Consequently  (we  may  paraphrase  his  argu- 
ment) space-discrimination  cannot  he  an  essential  part  of  the 
process  of  perceiving  motion^  at  least  when  rapid.  Further- 
more, and  now  passing  over  into  the  region  of  time,  motion 
can  be  seen  as  motion  even  when  its  duration  is  far  less  than 
the  least  time  that  permits  us  to  notice  succession.  If  instead 
of  making  the  excursion  through  a  shorter  and  shorter  dis- 
tance, the  extent  of  the  excursion  remain  constant  and  the 
movement  be  made  more  and  more  rapid,  Exner  found  that, 
even  when  the  motion  occupied  a  time  so  brief  that  two 
sparks,  the  one  at  the  beginning,  the  other  at  the  end  of  such 
duration,  seemed  absolutely  simultaneous,  the  motion  was 
still  perceptibly  motion.  Consequently  (so  runs  the  thought) 
time-discrimination  cannot  be  an  essential  part  of  the  process 
of  perceiving  motion.^ 

As  regards  the  first  part  of  this  argument — the  part  that 
deals  with  space-discrimination — I  may  perhaps  refer  to 
experimental  evidence  already  offered  by  myself  tending 
strongly  (so  it  seems  to  me)  to  show  that  the  facts  upon 
which  the  argument  is  based  were  gathered  far  too  narrowly.^ 
If,  instead  of  relying  on  the  two-point  method  of  determining 
the  space-threshold,  we  employ  a  method  involving  the  ap- 
parent dislocation  or  coincidence  of  two  parallel  lines  placed 
end  to  end,  the  power  to  detect  differences  of  position  is 
approximately  the  same  as  that  for  the  perception  of  move- 
ment. And  consequently  a  full  half  of  the  ground  for  believ- 
ing in  the  psychic  simplicity  and  independence  of  movement 
caves  away. 

1  Cf.  the  argument  as  set  forth  in  James's  Principles  of  Psychology,  II.,  172.  The 
refs.  to  Exner  are  found  below. 

2 'Visible  Motion  and  the  Space-threshold,'  Psychological  Review,  IX.,  433  flF.; 
and  cf.  Bourdon:  La  perception  visuelle  de  Vespace,  pp.  144  f.,  with  the  refs.  there  given. 


264  G.  M.  STRATTON 

I.  Previous  Experimental  Work 
Exner's  experiments  upon  the  time-factor  in  the  percep- 
tion of  visual  movement  were  in  substance  as  follows.^  Using 
close-neighboring  electric-sparks,  he  found  that  with  eyes  at 
a  certain  distance  from  the  sparks  the  most  rapid  succession 
that  could  be  discerned  was  one  of  440-.  But  by  more  than 
doubling  the  distance  between  eye  and  sparks  and  thus  pro- 
portionately diminishing  the  visual  angle  between  the  sparks 
and  at  the  same  time  producing  an  illusion  of  movement  from 
one  to  the  other,  he  found  this  movement  still  noticeable 
when  the  time-interval  was  shortened  by  practice  to  I5<r. 
Substituting  for  the  electric  sparks  flashes  of  light  through 
two  apertures  in  a  screen,  Exner  could  tell  correctly  the  order 
of  sequence  when  the  flashes  were  45a  apart;  but  when  the 
portion  of  the  screen  between  the  two  apertures  was  cut  out 
and  otherwise  so  arranged  as  to  give  a  moving  light  between 
these  two  localities,  motion  could  still  be  perceived  when  its 
duration  was  but  140-.  Motion,  whether  real  or  apparent, 
thus  had  power,  it  seemed,  to  reduce  the  limit  below  which 
a  visual  stretch  of  brightness  appeared  as  a  synchronous  and 
uniform  illumination.  Exner's  data  for  this  conclusion 
were  obtained  from  foveal  vision;  with  eccentric  vision  he 
found  it  impracticable  to  exclude  the  appearance  of  motion; 
he  was  thus  unable  to  compare  in  this  region  the  times  of 
just-visible  motion  and  of  succession  apart  from  movement. 
Charpentier,  who  next  in  any  significant  way  approached 
the  problem,  employed  a  method  much  the  same  as  the  second 
of  Exner's  described  above,  yet  with  this  important  difference, 
— that  instead  of  producing  discrete  succession  by  separated, 
although  neighboring  spots  of  light,  he  arranged  a  vertical 
slit,  of  which  he  could  illuminate  independently  the  upper 
and  the  lower  half,  and  thus  the  sensations  whose  sequence 
or  simultaneity  was  to  be  caught  appeared  in  absolute  juxta- 
position. He  found:  (i)  that  if  the  time-interval  between 
the  halves  be  slight,  they  seem  illuminated  simultaneously; 

^  Exner,  'Experimentelle  Untersuchung  der  einfachster  psychischen  Processe 
Pfliiger's  Archiv,  VII.,  6oi  ff.;  VIII.,  526  ff.;  XL,  4035.;  'Ueber  das  Sehen  von  Be- 
wegungen  und  die  Theorie  des  zusammengesetzten  Auges,'  Sitzungsb.  d.  kaiserl.  Akad, 
d.  Wissens.  Math.-Naturw.  CI,  LXXIL,  Ft.  in  (Vienna,  1875),  pp.  156 ff. 


PERCEPTION  OF  MOVEMENT  265 

(2)  with  increase  of  this  interval  the  illuminations  seem  dis- 
tinct in  time,  but  it  is  impossible  to  say  which  comes  first; 

(3)  only  with  still  greater  increase  of  the  time-interval  can 
one  say  which  is  first;  and  (4)  the  absolute  duration  of  the 
illumination  of  each  half  seems  not  to  affect  this  detection 
of  sequence.  On  the  average  (and  apparently  from  but  a  few 
experiments)  he  found  a  noticeable  difference  when  the  be- 
ginnings of  the  lights  differed  by  270-.^  With  regard  to 
Charpentier's  discussion  of  the  error  we  make  in  the  apprecia- 
tion of  succession — the  illusion  that  successive  lights  are 
simultaneous — it  was  contended  by  Bloch  that  this  error 
entirely  disappears  if  the  successive  s'timulations  do  not  fall 
upon  identical  parts  of  the  retina,^ — a  surprising  criticism, 
apparently  based  neither  on  any  right  understanding  of 
Charpentier  nor  upon  any  reliable  experiment  of  Bloch's  own. 
Charpentier,  in  reply ,^  after  clearing  up  the  matter  of  method, 
says  briefly  and  with  restraint,  that  while  he  cannot  deny 
that  the  succession  may  continue  to  appear  to  the  very  end, 
he  is  quite  unable  to  notice  it  himself.  Neither  Charpentier 
nor  Bloch  seem  to  have  made  more  than  a  few  trials  nor  to 
have  concerned  themselves  with  obtaining  comparable  data 
in  the  region  of  movement,  and  so  of  clearing  up  the  problem 
more  directly  before  us. 

This  problem  was,  however,  held  distinctly  in  mind  by 
Stern,^  who  arrives  at  a  conclusion  opposed  to  that  of  Exner. 
But  since  his  own  experimental  contribution  is  confined  to 
the  spatial  rather  than  to  the  temporal  side  of  the  question,^ 
it  hardly  need  here  be  reproduced. 

1  Charpentier,  'Sur  I'appreciation  du  temps  par  la  retine,'  Seance  et  Memoires  de 
la  Societe  de  Biologie,  Vol.  IV.,  8th  Series  (Paris,  1887),  pp.  360-1;  'Nouvelle  note  sur 
i'appreciation  du  temps  par  la  retine,'  ibid.,  pp.  373-5. 

^ Bloch,  'Note  sur  les  sensations  visuelles,'  ibid.,  pp.  391-3. 

3  Charpentier,  'Note  sur  le  synchronisme  apparent,'  etc.,  ibid.,  pp.  447-8. 

4 'Die  Wahrnehmung  von  Bewegungen  vermittelst  des  Auges,'  Zeitschrift  fur 
Psychologie,  etc.,  VII.  (1894),  321  ff.  Stern  is  in  the  neighborhood  of  the  time-side  of 
the  problem  only  when  he  considers  the  most  favorable  rhythm  of  motion  if  the  motion 
is  to  be  noticed.  Cf.  my  own  discussion  and  opposing  results,  in  'Visible  Motion  and 
the  Space  Threshold,'  Psychological  Review,  IX.,  433  ff. 

'This  is  true  also  of  the  work  of  Basler,  'Ueber  das  Sehen  von  Bewegungen,' 
Pfliiger's  Archiv,  1906,  XV.,  582,  1908;  CXXIV.,  313. 


266  G.  M.  STRATTON 

Weyer,  experimenting  with  successive  electric  sparks, 
given  (it  would  seem)  from  a  single  sparker  and  consequently 
appearing  at  one  identical  point,  brought  out  some  interesting 
facts  concerning  the  detection  of  sequence;  but  his  interest 
was  not  directly  in  our  problem,  and  he  made  no  attempt  to 
obtain  in  the  field  of  movement  data  with  which  his  results 
upon  succession  might  be  compared.  He  found,  however, 
that  in  starting  with  so  brief  an  interval  that  the  two  sparks 
appeared  as  one,  there  were  certain  definite  intermediate 
stages  before  this  appearance  of  precise  singleness  of  spark 
yielded  to  a  clear  appearance  of  succession.  The  apparently 
unitary  illumination  began  to  drag,  or  'persist'  when  the 
interval  was  somewhat  increased — to  about  i2o-,  with  day- 
light adaptation.  With  still  greater  increase — to  an  interval 
of  25(7-300- — there  came  a  slight  flicker.  Finally,  when  the 
interval  was  increased  to  43o'-53cr,  the  two  sparks  appeared 
in  clear  succession.^ 

With  Bourdon  there  was  distinct  interest  in  our  particular 
problem,  and  he  accordingly  gathered  data  both  of  succession 
and  of  movement.  He  used  small  areas  of  white  paper  at- 
tached to  a  revolving  drum,  so  arranged  that  they  produced 
an  appearance  now  of  motion  and  now  of  mere  sequence  of 
neighboring  lights.  When  the  conditions  were  on  the  whole 
most  favorable,  he  found  motion  recognizable  by  direct  vision 
at  a  duration  of  270-.  With  discrete  succession  instead  of 
motion,  he  found  it  impossible  to  pass  judgment  when  the 
interval  was  only  i6o-;  his  right  judgments  exceeded  the 
wrong  when  the  interval  was  200-;  when  the  interval  was 
increased  to  480-,  he  recognized  with  certainty  the  order  in 
which  the  lights  disappeared.  His  conclusion  is  that  the 
perception  of  motion  has  no  such  preeminence  over  that  of 
succession  as  Exner  claimed;  indeed,  the  thresholds  of  these 
two  kinds  of  perception  come  to  nearly  the  same  measure.^ 

^  Weyer, '  Zeitschwellen  gleichartiger  und  disparater  Sinneseindriicke,'  Wundt's 
Philosop'kische  Studien,  XIV.,  616;  XV.,  67. 

'  Bourdon,  La  perception  visuelle  de  Vespace,  pp.  187  ff.  Marbe  {Theorie  der  kine- 
matographischen  Projectionen,  1910,  p.  62)  has  added  still  later  experiments,  but  again 
upon  but  one  of  the  two  sides  important  for  the  present  question.  He  finds  that  when 
a  series  of  13  miniature  incandescent  lights  flash  in  succession  at  a  rate  wherein  the  in- 
terval between  the  flashes  of  adjacent  lights  is  reduced  to  iiff  the  impression  of  move- 
ment ceases. 


PERCEPTION  OF  MOVEMENT  267 

Only  Exner  and  Bourdon,  then,  maintained  in  the  two 
regions  that  must  of  necessity  here  be  compared,  a  single 
unchanging  method  applied  under  inner  and  outer  conditions 
that  also  in  the  main  remained  unchanged.  And  their 
excellent  work,  I  have  ventured  to  think,  still  leaves  room, 
even  apart  from  a  certain  conflict  of  outcome,  for  some  doubt 
and  Inquiry.  With  Bourdon,  for  instance,  it  is  clear  that 
exactly  the  same  conditions  were  not  maintained  both  in  his 
experiments  upon  succession  and  in  those  upon  motion.  The 
lines  that  passed  the  slit  were  not  alike  in  the  two  cases;  and 
this  might  have  affected  the  apparent  intensity  of  the  sensa- 
tions; the  slit  through  which  the  stimulus  appeared  was,  in 
the  case  of  the  motion,  horizontal  and  I  mm,  wide,  in  the  case 
of  succession  it  was  vertical  and  0.4  mm.  wide;  the  distance 
between  the  observer  and  the  lights  was  different  In  the  two 
cases.  All  these  discrepancies  should  be  removed,  and  the 
two  series  to  be  compared  should  run  on  abreast  to  avoid  any 
possible  advantage  from  the  difference  of  training  and  prac- 
tice. In  particular  It  has  seemed  to  me  desirable  to  regard 
as  an  open  question  what  the  eifect  of  certain  variations  of 
method  would  be;  and  farther,  just  what  space  relation  should 
subsist  between  the  successive  lights,  if  the  conditions  were 
to  be  most  favorable  for  the  detection  of  succession.  Will 
succession  best  be  observed  when  the  successive  spots  of  light 
are  closer  together  or  farther  apart;  when  they  are  In  juxta- 
position or  when  some  distance  Intervenes.''  We  should  dis- 
cover the  most  favorable  conditions  for  each  class  of  observa- 
tions before  we  could  finally  decide  as  to  their  relative 
superiority. 

It  would  be  idle  to  claim  that  the  programme  finally 
adopted  covers  the  ground;  all  that  should  be  said  Is  that  it 
aims  to  clear  up  an  obscure  point  or  two.  A  part  of  It  has 
been  carried  out  by  an  able  student  of  mine,  Mr.  Brewer, — 
the  part  dealing  with  successions  that  are  not  only  temporally 
but  spatially  separate.  And  his  report  accompanies  and  may 
be  regarded  as  an  Intimate  part  of  this  discussion.^  His 
experiments    had    shown    a    regular   reduction    of   the    time- 

'  Brewer,  The  Psychology  oj  Change:  On  some  Phases  of  Minimal  Time  by  Sight, 
in  the  present  number  of  the  Psychological  Review. 


268  G.  M.  STRATTON 

threshold  for  succession,  as  the  visual  angle  was  reduced.  For 
myself,  I  felt  tempted  to  push  this  reduction  to  its  very  limit 
by  making  trial,  in  the  region  of  time,  of  a  slight  modification 
of  method  that  has  proved  of  marked  effect  in  studying 
movement  upon  its  spatial  side.  For  it  will  perhaps  be 
remembered  by  some  that  a  change  in  the  manner  of  testing 
the  space-threshold,  whereby  lines  were  placed  end  to  end, 
instead  of  side  by  side,  had  reduced  the  space-threshold  at 
least  five-fold  and  perhaps  ten-fold;  had  reduced  it  from  a 
visual  angle  of  30"  with  stars,  or  of  60"  if  we  keep  to  lines,  to  a 
visual  angle  of  approximately  j" .^  Here  in  placing  the 
lines  end  to  end,  there  is  perfect  proximity  of  the  impressions 
to  be  compared,  yet  without  the  easy  fusion  which  befalls 
lines  side  by  side.  An  analogous  procedure  in  the  realm  of 
time  would  be  to  have  the  succession  of  flashes  come,  not 
upon  the  same  points  of  the  retina  where  persistence  of 
impression  would  conceal  the  time-interval,  but  upon  adja- 
cent points,  yet  neither  with  confusion  by  overlapping  cir- 
cles of  irradiation  nor  with  any  insistent  illusion  of  movement. 
This  seemed  attainable  by  means  of  a  narrow  slit,  half  of 
which  should  be  lighted  at  one  instant,  and  half  at  another, — 
the  time-interval  between  these  illuminations  to  be  variable 
and  definitely  known.  The  plan,  then,  involved  the  method 
already  employed  briefly  by  Charpentier,  and  at  the  same  time 
the  gathering  of  exactly  comparable  data  regarding  movement. 

II,  Experiments  with  Pendulum  Device 
In  the  present  experiments  two  different  arrangements  of 
apparatus  were  employed.  The  first  group  of  experiments 
was  with  the  pendulum  described  in  Brewer's  paper  already 
mentioned;^  but  with  attachments  other  than  those  he  used. 
Imagine  a  plate  of  aluminum  just  above  the  pendulum's  bob, 
lying  in  the  plane  of  oscillation.  In  this  plate  and  at  about  a 
distance  of  i  m.  from  the  point  of  suspension  of  the  pendu- 
lum there  was  a  vertical  radial  slit  5  cm.  long,  with  a  mean 

1  'A  New  Determination  of  the  Minimum  Visibile,'  Psychological  Review,  VII., 
249;  'Visible  Motion  and  the  Space-Threshold,'  Psychological  Review,  IX.,  433  ff. 
Cf.  Bourdon,  La  perception  visuelle  de  Vespace,  pp.  144  ff. 

2  See  pp.  25  f. 


PERCEPTION  OF  MOVEMENT  26^ 

width  of  4.5  mm.  later  narrowed  to  i  mm.  The  pendulum 
with  this  radial  slit  swung  behind  a  stationary  screen  which 
also  had  a  vertical  slit  with  parallel  sides  2  mm.  apart  and 
long  enough  to  expose  the  full  length  of  the  slit  behind. 
Back  of  both  screen  and  pendulum  was  ground  glass  evenly 
illuminated  by  six  i6-c.p.  incandescent  lamps.  With  certain 
adjustments  the  observer,  at  a  distance  of  2  m.,  perceived  a 
momentary  illumination  of  the  vertical  slit  in  the  stationary 
screen;  while  with  other  adjustments  the  upper  and  lower 
half  of  the  radial  slit  in  the  pendulum  could  be  mutually  so 
displaced  as  to  present  to  the  observer  the  two  halves  of  the 
slit  illuminated  in  quick  succession.  The  exact  point  in. 
the  front  slit  where  these  two  halves  had  their  common 
border  was,  for  the  sake  of  preparatory  fixation,  indicated 
by  white  horizontal  arrows,  while  the  time-interval  between 
the  illumination  of  the  two  halves  could  be  exactly  controlled 
by  a  scale  obtained  chronographically. 

The  impression  of  movement,  for  the  companion  experi- 
ments, was  obtained  by  another  attachment  essentially  the 
same  as  that  described  in  Brewer's  paper.^  It  need  hardly 
be  said  that  here  the  same  width  of  slits  and  intensity  of 
illumination  of  background,  was  maintained  as  in  the  experi- 
ments on  succession,  and  the  extent  of  the  motion  was 
identical  with  the  length  of  the  two  illuminated  halves  then 
used.^  And  in  all  cases  the  two  sets  of  experiments  were  so 
arranged  as  to  exclude  any  difference  of  practice  or  fatigue 
in  the  two  groups.  There  were  two  observers  In  the  present 
group  of  experiments,  as  well  as  in  a  second  group  later 
to  be  described.  To  Dr.  Brown,  who  gave  unstintlngly  of 
time  and  good  will  In  these  none-too-interesting  tests,  I 
acknowledge  my  great  indebtedness. 

Since  the  tendency  here  is  to  see  every  impression  as 
motion  and  indeed  as  motion  in  some  particular  direction, 

iSee  p.  258. 

2 Brewer's  experiments,  It  will  be  seen,  showed  that  the  optimal  excursion  for 
perceiving  motion  is,  unlike  that  of  succession,  by  no  means  near  zero.  With  some 
it  seems  to  lie  at  least  as  far  out  as  a  visual  angle  of  18.6'.  The  motion  in  the  present 
experiments  was  some  five  times  this  extent,  and  in  all  probability  included  the  optimal 
excursion  for  my  observers. 


270 


G.  M.  STRATTON 


the  'method  of  serial  groups'^  was  used  Instead  of  the  more 
common  gradation  method.  The  procedure  was  '  unzvissent- 
lich\'  and  but  a  single  movement,  or  pair  of  lights  in  succes- 
sion, was  oflfered  for  judgment.  At  first  an  attempt  was  made 
to  distinguish,  in  each  judgment,  not  only  between  motion 
and  succession  but  also  between  the  two  orders  of  succession 
(upper  first;  lower  first)  and  the  two  directions  of  movement 
(down;  up).  But  prepossession  soon  proved  too  strong,  and 
so  wide  a  range  of  intervals  was  needed  to  catch  all  phases  of 
these  judgments  that  I  finally  abandoned  the  attempt  to 
obtain  thresholds  for  the  correct  perception  of  the  order  of 

Table  I 

Observer  B 

Thresholds  expressed  in  mm.  (l  mm.  =  JT.Jff) 


Order  of  Presentation 

With  Two  Successive  lyights 

With  Moving  I,ight 

Above-below 

Below-above 

Downward 

Upward 

With  wider  slit. 

12 
II 

18 
15 

17 
17 
IS 
15 

35  + 

35 

45 

25 
30 

25 

Average. 

14 

16 

38.3 

26.7 

With  narrower  slit. 

15 
20 

20 

22 

40 
35 

25 
20 

Average. 

17-5 

21 

37-5 

22.5 

Combined  average. 

15.2 

17.7 

38 

25 

Average  for  the  two  orders 
of  presentation. 

16.4 

31-5 

succession  and  for  the  direction  of  motion,  which  are  un- 
questionably distinct  from  the  thresholds  for  the  perception 
of  mere  succession  and  mere  motion.  I  felt  content  to  note 
the  point  at  which  actual  succession  on  the  one  hand  and 
motion  on  the  other,  no  longer  seemed  sheer  simultaneity  of 
Illumination.  Yet  the  observers  were,  through  a  large  part 
of  the  present  group  of  experiments,  more  or  less  concerned 
to  make  out  more  exactly  the  nature  of  whatever  departure 
from  simultaneity  they  noticed,  and  so  their  judgments  were 
not  quite  untrammelled  and  homogeneous.  Yet  they  should 
perhaps  be  entered,   since  in  several  ways   they  are   worth 

'See  Psychological  Review,  IX.,  444  ff. 


PERCEPTION  OF  MOVEMENT 


271 


comparing  with  the  group  to  be  spoken  of  some  pages  hence. 
Each  'determination'  given  in  the  tables  accompanying 
(Tables  I.  and  11.)  represents  never  less  than  50  nor  more 
than  100  separate  judgments.  In  all,  there  were  between 
1,500  and  1,600  judgments  in  this  group,  apart  from  many 
preliminary  experiments  and  the  half  dozen  judgments  at  the 
opening  of  each  hour  for  'warming-up.' 

Table  II 

Observer  S 
Thresholds  expressed  in  mm.  (i  mm.  =  I.S<t) 


Order  of  Presentation 

with  Two  Successive  Ivights 

With  Moving  Light 

Above-below 

Below-above 

Downward 

Upward 

With  wider  slit. 

9 
8 

10 
10 

20 
20 
20 
20 

10 

IS 
10 

20 
20 
15 

Average. 

9.2 

20 

II.7 

18.3 

With  narrower  slit. 

12 
13 

13 

23 

8 
8 

IS 

17 

Average, 

12.S 

18 

8 

16 

Combined  average. 

10.3 

19-3 

10.2 

17.4 

Average  for  the  two  orders 
of  presentation. 

14.8 

13-8 

The  tables  show  that  for  Observer  B.  there  was  a  decided 
advantage  on  the  side  of  succession,  and  for  Observer  S.,  no 
marked  advantage  either  way,  although  a  slight  advantage 
appears  on  the  side  of  motion.  Whatever  gain  here  accrues 
to  'succession'  is  not  in  any  wise  due  to  an  illusory  motion 
when  mere  succession  was  offered.  On  the  contrary,  with 
both  observers  the  presentations,  whether  of  succession  or  of 
motion,  when  just  rising  above  the  threshold  were  perceived 
as  succession  far  more  often  than  as  motion.  The  usual 
course  of  the  judgments  was  this;  with  the  longer  times  there 
was  a  clear  discrimination  between  succession  and  motion; 
and  then,  with  briefer  times,  the  presentation  was  called 
'successive'  or  'different,'  meaning  that  it  was  not  a  single 
simultaneous  illumination.  Even  with  actual  motion,  there- 
fore, the  observer  failed  to  notice  the  motion,  but  noticed 


272  G.  M.  STRATTON 

only  non-simultaneity.  And  this  lower  threshold  is  entered 
in  the  tables  even  in  the  case  of  motion.  Where,  with  B.  for 
example,  the  thresholds  for  motion  are  entered  as  300-  and 
350-,  this  indicates  the  point  at  which  a  departure  from  simul- 
taneity was  evident;  motion  was  discerned  as  motion  only  at 
400-  and  450-  respectively;  and  with  S.  the  detection  of  motion 
required  a  value  even  higher  in  its  ratio  to  that  of  mere 
succession. 

Furthermore,  there  is  a  difference,  in  some  cases  quite 
marked,  between  the  thresholds  for  the  different  orders  of 
presentation.  Thus  for  both  B.  and  S.  the  threshold  is 
lower  when,  in  the  case  of  succession,  the  upper  half  of  the 
slit  is  illuminated  before  rather  than  after  the  lower.  And 
with  motion  also  the  direction  affects  the  threshold,  although 
here  the  two  observers  do  not  show  a  like  divergence,  since 
B.  best  catches  motion  upward,  while  with  S.  motion  down- 
ward has  the  advantage.  But  of  this  phenomenon  more  will 
be  said  in  connection  with  the  later  experiments. 

III.  Experiments  with  Wheel  Apparatus 
The  set  of  experiments  just  reported  seemed  to  me  incon- 
clusive because  of  a  growing  doubt  both  of  the  apparatus  and 
of  the  method.  The  puzzling  disagreement  of  results  obtained 
in  the  different  orders  of  presentation,  though  the  observer 
did  not  have  to  decide  which  order  was  given  him  (to  which 
attention  has  just  been  drawn),  made  me  perhaps  unwarrant- 
ably inclined  to  believe  that  this  inconsistency  might  be  due 
to  some  want  of  rigidity  in  the  instrument.  And  hesitation 
arose,  too,  from  the  very  fact  that  the  values  obtained  bore, 
at  least  in  the  case  of  one  of  the  two  observers,  a  relation  so 
decidedly  the  reverse  of  that  in  the  classic  results. 

Consequently  an  entirely  new  apparatus  was  constructed 
by  a  skilful  instrument-maker — a  pendulum-wheel  suggested 
by  a  device  of  Sanford's,^  but  departing  from  it  in  several 
respects.  From  a  sheet  of  aluminum  34  i^i.  thick,  there  was 
cut  a  narrow  circular  rim  20  in.  in  diameter,  having  thin  poke- 
like connections  with  its  center.  At  the  center  there  was  a  steel 
axle  with  ball-bearings  resting  upon  a  rigid  frame  and  base, 

'Sanford,  American  Journal  of  Psychology,  VI.,  581  fF. 


PERCEPTION  OF  MOVEMENT  273 

upon  which  there  were  levelling  screws  and  a  circular  spirit 
level.  To  the  rim  of  this  skeleton  wheel  was  carefully  fitted 
a  weight  and  catches,  so  that  with  the  weight  high  upon  one 
side,  when  one  of  the  catches  was  released,  the  wheel  revolved 
until  the  weight  rose  high  upon  the  opposite  side;  and  there 
at  its  extreme  excursion  the  wheel  was  caught  and  the  return 
of  the  weight  prevented.  In  preparation  for  the  next  fall,  the 
rotation  of  the  wheel  was  completed  by  hand,  and  by  means 
of  the  catch  the  weight  was  held  high  upon  the  side  whence  it 
first  fell. 

Upon  the  axle  of  the  wheel  was  a  screw  holding  two  large 
black  bristol  disks,  one  of  which  was  fixed  by  additional  screws 
upon  the  rim,  the  other  being  movable  and  to  be  set  instantly 
at  any  position  desired.  In  these  disks  there  were  in  principle, 
the  same  devices  for  producing  succession  and  movement  as 
with  the  pendulum  before.  Thus  any  order  and  interval  of 
succession,  any  direction  and  speed  of  movement,  could  be 
had  at  will.  Proper  scaling  in  thousandths  of  a  second  was 
provided  beforehand  by  tuning-fork  records  on  the  disk,  the 
tuning-fork  itself  having  of  course  been  first  carefully  cor- 
rected. 

The  method  was  such  as  to  avoid  any  extraneous  advan- 
tage accruing,  by  practice  or  fatigue,  to  either  of  the  forms  of 
perception.  Experiments  upon  succession  and  upon  motion 
were  from  the  first  mingled  in  equal  number  at  every  sitting; 
nor  did  the  observer  himself  know  in  any  case  whether  the 
stimulus  to  be  offered  him  involved  motion  or  succession 
merely,  nor  was  he  told  this  after  his  judgment  had  been 
given.  But  a  single  movement,  a  single  pair  of  successive 
lights,  were  given  for  any  one  judgment.  And  further  it 
seemed  advisable,  in  view  of  what  had  happened  in  the 
preceding  set  of  experiments,  to  simplify  the  task  of  the 
observer  and  render  his  judgments  more  direct  and  trust- 
worthy. Hitherto,  as  already  has  been  indicated,  the  judg- 
ments showed  some  embarrassment  before  the  several  possible 
queries:  (i)  Was  the  impression  throughout  its  stretch  simul- 
taneous, or  was  there  some  departure  from  perfect  simul- 


274  G.  M.  STRATTON 

tanelty?  (2)  If  there  was  such  a  departure,  had  It  the  char- 
acter of  a  successive  illumination  of  the  two  halves  of  the 
slit;  or  of  a  motion?  (3)  If  a  succession,  did  the  lower  half 
of  the  slit  flash  before  or  after  the  upper?  (4)  If  a  motion, 
was  this  upward,  or  down?  Now  the  observer  is  111  at  ease 
before  so  many  questions,  and  his  nicety  of  judgment  Is  apt 
to  be  affected  by  the  attempt  to  keep  his  mind  at  once  open 
to  so  many  aspects  of  the  impression,  and  in  the  effort  to 
answer  secondary  questions  the  answers  to  primary  are  often 
obscured  or  lost.^ 

Accordingly  In  this  whole  group  of  experiments,  even 
from  the  start,  the  observer  was  asked  to  confine  his  attention 
to  the  first  of  the  four  questions  just  listed.  Additional 
judgments  were  occasionally  volunteered;  and  although 
noted,  they  were  not  encouraged.  The  method  again  was, 
at  bottom,  that  of  serial  groups.  Inasmuch  as  a  number  of 
fixed  Intervals  or  durations  were  selected  and  repeated;  and 
interspersed  with  these  were  frequent  cases  where  the 
interval  or  duration  was  reduced  to  zero.  Yet  instead  of 
adhering  to  a  particular  interval  or  duration  until  its  group 
was  complete,  and  exchanged  for  a  new  group  and  so  on  until 
the  threshold  had  been  passed,  there  was  no  attempt  to 
determine  a  threshold  In  the  accepted  sense,  but  only  by  a  full 
display  of  right  and  wrong  cases,  with  each  interval  or  dura- 
tion, to  reveal  the  relative  facility  of  perceiving  movement 
and  succession.  The  following  partial  series  of  actual  stimuli 
presented,  where  the  distribution  Is  quite  by  chance,  will 
perhaps  make  clear  the  procedure  just  described. 
0(x  motion  (  =  slmult.  Ilium,  of  entire  slit). 

lOo"  succession,  upper-lower. 

20a-  motion,  upward. 

300-  succession,  lower-upper. 
Oct  succession  (  =  slmult.  ilium,  of  entire  slit). 

io<r  motion,  upward. 
Oo-  succession. 

25or  succession,  upper-lower. 

^See  the  argument  offered  by  Brown  ('The  Judgment  of  Difference,'  University 
0/  California  Publications  in  Psychology,  I.,  28  ff .)  for  a  simple  alternative  in  the  question 
— an  argument  that  has  had  great  weight  with  me. 


PERCEPTION  OF  MOVEMENT 


275 


Table  III 

(Judgments 

UPON  Single  Presentations; 
Observer  B 

Discrete  Succession 

Direct  Vision) 

Interval 1 

Successes 

Failures 

300- 

12 

0 

2S<r 

12 

0 

200- 

13 

I 

iS«r 

10 

4 

lo<r 

10 

4 

SO- 

6 

8 

Totals. 

63 

17 

Duration 

Successes 

Failures 

30<r 

8 

4 

25<r 

9 

3 

2O0- 

10 

4 

is<^  ■ 

6 

8 

loo- 

2 

12 

S"- 

Totals. 

6 

41 

8 
39 

instantaneous 

illums.,  50  were  judged  'simult. 

Table  IV 

,'  22  'non-simult.' 

(Judgments 

UPON  Single  Presentations; 
Observer  S 
Discrete  Succession 

Direct  Vision) 

Interval 

Successes 

Failures 

30<r 

10 

2 

2S<r 

II 

I 

20(r 

12 

0 

is<»- 

9 

3 

loo- 

s<»- 

Totals. 

S 
6 

S3 

Motion 

7 

19 

Duration 

Successes 

Failures 

30(r 

12 

0 

2S<r 

9 

3 

20<r 

10 

2 

IS"- 

II 

I 

icxr 

5"- 

7 
_6 

S 
6 

Totals. 

SS 

17 

Of  72  instantaneous  illums.,  47  were  judged  'simult.,'  26  'non-simult.' 

^  'Interval'  here  and  elsewhere  means  the  time  between  beginning  and  beginning, 
or^end  and  end,  of  the  two  successive  flashes. 


276 


G.  M.  ST  RAT  TON 


20a  motion  upward. 

150-  succession,  lower-upper. 
5<T  motion,  downward. 
Go-  succession. 

300-  motion,  upward. 
Go-  motion,  etc. 

The  following  tables  exhibit  the  results  of  these  experi- 
ments. 

Method  of  Paired  Presentations. — Before  discussing  these 
results,  let  me  offer  also  those  of  another  method,  used  as  a 
check.  Here  the  apparatus  and  procedure  was  in  all  respects 
as  just  described,  except  that  there  was  given,  in  sequence, 
two  presentations;  namely,  a  zero  case — where  there  was 
absolute  simultaneity  of  illumination — and  a  case  where  there 
was  actual  succession  or  motion.  The  observer  was  told  that 
there  would  be  two  presentations,  one  of  which  would  be  a 
simultaneous  illumination  of  the  entire  slit,  the  other  a 
departure  from  such  simultaneity;  and  that  his  task  was 
simply  to  tell  whether  the  simultaneous  illumination  occurred 
first  or  second  in  the  pair.  The  two  presentations  were  then 
given,  with  as  little  time  between  as  could  be  with  the  adjust- 
ment required  (about  4  seconds),  and  no  judgment  was  passed 
until  after  the  appearance  of  the  second  of  the  pair.     The 


Table  V 

(Judgment 

BY  Pairs;  Direct  Vis 

sign) 

Observer  B 

Discrete   Succession 

Interval 

Successes 

Failures 

20<r 

II 

I 

I5<^ 

10 

2 

lOff 

8 

4 

Totals. 

_6 

35 

Motion 

6 

13 

Duration 

Successes 

Failures 

200- 

7 

5 

IS**" 

8 

4 

10(r 

8 

4 

Totals. 

_4 
27 

8 
21 

PERCEPTION  OF  MOVEMENT 


277 


Table  VI 

(Judgment  by  Pairs;  Direct 

Vision) 

Observer  S 

Discrete  Succession 

Interval 

Successes 

Failures 

ZO(T 

14 

0 

IS'' 
I0<r 

10 
II 

4 
3 

S<' 
Totals. 

II 

46 

Motion 

_3 
10 

Duration 

Successes 

Failures 

200- 

13 

I 

iS«r 
loo- 
Totals. 

13 
7 
6 

39 

I 

7 

8 

17 

observer  was  ignorant  of  the  actual  order,  and  this  order  itself 
was  irregularly  changed.  The  following  tables  exhibit  the 
results  obtained. 

Examination  of  the  results  of  these  two  different  pro- 
cedures discloses  that  with  neither  of  the  observers,  nor  by 
either  method,  is  there  an  advantage  for  motion  over  succes- 
sion. And  consequently  the  new  apparatus  and  simplified 
task  for  the  observer  brings  the  same  general  relation  of 
values  as  were  obtained  in  the  first  set  of  experiments  with 
the  pendulum.  Observer  B.  now,  as  before,  can  more  readily 
detect  a  departure  from  simultaneity  in  the  illumination  when 
departure  actually  is  of  succession  rather  than  of  motion. 
Observer  S.  again,  for  a  part  of  the  set — when  there  were 
single  presentations — shows  about  equal  facility  with  either 
kind  of  stimulus;  but  with  double  presentations  shows 
greater  ease  in  dealing  with  successsion. 

Any  one  interested  in  method,  and  in  the  psychological 
indications  arising  from  differences  therein,  will  perhaps  feel 
inclined  to  compare  more  closely  the  outcome  by  single 
presentation  (Tables  III.  and  IV.)  and  by  double  (Tables  V. 
and  VI.).  It  will  be  seen  that  Observer  B.  has,  so  far  as  dis- 
crete succession  is  concerned,  a  slightly  greater  success  by 
the  method  of  double  presentation,  and  with  motion  he  shows 


278 


G.  M.  STRATTON 


a  decidedly  higher  ratio  of  successes  to  failures  when  the  pre- 
sentation is  in  pairs.  Observer  S.,  when  discrete  sequence 
is  offered,  succeeds  markedly  better  with  pair-presentations 
than  with  single-presentations;  when  motion  is  offered,  the  ad- 

Table  VII 

Observer  B.     Direct  Vision 
With  Discrete  Succession 


Time  Interval 

Judgment  by  Single  Presen- 
tation 

Judgment  by  Double  Presen- 
tation 

Successes 

Failures 

Successes 

Failures 

20<T 

loo- 

13 
10 
10 

6 

I 

4 
4 

8 

II 

10 

8 
6 

I 

2 

4 
6 

Totals 

39 

17 

35 

13 

Ratio  of  successes  to  failures 

2.3  :  I 

2.7:1 

With   Motion 


Duration 

Judgment  by  Single  Presen- 
tation 

Judgment  by  Double  Presen- 
tation 

Successes 

Failures 

Successes 

Failures 

20cr 
loo- 

10 

6 
2 
6 

4 

8 

12 

8 

7 
8 
8 
4 

s 

4 
4 

8 

Totals 

24 

32 

27 

21 

Ratio  of  successes  to  failures 

0.7s  :  I 

1.3  :l 

Table  VIII 

Observer  S.     Direct  Vision 
With  Discrete  Succession 


Interval 

Judgment  by  Single  Presen- 
tation 

Judgment  by  Double  Presen- 
tation 

Successes 

Failures 

Successes 

Failures 

200- 
IS<r 
IOC- 

12 

9 

5 
6 

0 
3 
7 
6 

14 
10 
II 
II 

0 
4 

3 
3 

Totals 

32 

16 

46 

10 

Ratio  of  successes  to  failures 

2  :  I 

4.6  :  I 

PERCEPTION  OF  MOVEMENT 


279 


With  Motion 


Duration 

Judgment  by  Single  Presen- 
tation 

Judgment  by  Double  Presen- 
tation 

Successes 

Failures 

Successes 

Failures 

20cr 

loo- 

10 
II 

7 
6 

2 

I 

5 
6 

13 

13 

7 

6 

I 
I 

7 
8 

Totals 

34 

14 

39 

17 

Ratio  of  successes  to  failures 

2.4:1 

2.3  :  I 

vantage  for  the  method  in  which  pairs  of  presentations  occur 
disappears.  The  following  tables  (VII.  and  VIII.)  in  which 
the  comparable  values  are  isolated  and  set  side  by  side  and 
summed,  will,  I  trust,  make  this  more  clear. 

In  general  it  would  appear  that  a  greater  fineness  of  per- 
ception is  possible  by  the  method  of  paired  presentation  than 
by  that  of  single  presentation.  And  furthermore  there  is 
noticeable  in  the  values  obtained  by  the  method  of  paired 
presentations  a  somewhat  greater  regularity;  the  number  of 
successes  or  of  failures  keeps  better  step  with  the  change  in  the 
time-interval,  the  correlation  between  the  interval  employed 
and  the  success  of  perception  is  closer  when  this  method  is 
employed  than  when  its  rival. 

Experiments  with  Eccentric  Vision. — Such  was  the  evi- 
dence upon  the  main  problem,  so  far  as  a  foveal  vision  is 
concerned.  Experiments  were  tried  also  with  eccentric  vision, 
the  observer  fixating  with  both  eyes  a  point  20°  to  the  left 
of  the  slit  in  which  the  illumination  appeared.     Tables  IX. 

Table  IX 

Experiments  with  Eccentric  Vision 
Observer  B 


Time 

Discrete  Succession 

Motion 

Successes 

Failures! 

[Successes 

Failures 

300- 
250- 
20<r 
15<r 

11 

8 
6 
8 

I 

4 
6 

4 

10 

10 

6 

8 

2 
2 

6 

4 

Totals. 

33 

15 

34 

14 

28o 


G.  M.  STRATTON 
Table  X 

Experiments  with  Eccentric  Vision 
Observer  S 


Time 

Discrete  Succession 

Motion 

Successes 

Failures 

Successes 

Failures 

30ff 
25<r 
20<r 

lOff 

4 

3 

II 

9 
9 
9 

O 
I 
I 

3 
3 
3 

4 

4 

II 

9 
6 

4 

O 
O 

I 

3 
6 
8 

Totals. 

45 

II 

38 

i8 

and  X.  show  the  results  of  these  experiments.  The  presen- 
tations were  always  by- pairs;  the  procedure  was  in  all  other 
respects  as  last  described. 

Under  these  conditions  it  is  apparent  that,  with  Observer 
B.,  there  was  almost  equal  success  with  either  kind  of  stimulus, 
although  the  values  indicate  in  both  cases  a  higher  threshold 
than  with  direct  vision.  With  Observer  S.,  there  is  somewhat 
greater  facility  in  dealing  with  succession  than  with  motion, 
although  here  the  values  indicate  no  rise  of  the  threshold. 
Thus  in  this  region  as  in  others,  succession  is  certainly  at  no 
disadvantage  as  compared  with  movement. 

Absolute  Time  in  the  Results. — As  for  the  absolute  time- 
values  obtained  in  these  experiments,  they  run  considerably 
lower  than  we  have  been  accustomed  to  regard  as  obtaining 
here.  It  will  be  recalled^  that  Exner  found  150-  to  be  the 
duration  needed  for  perceiving  motion;  450-,  for  discrete  suc- 
cession. Bourdon  recognized  motion  at  270-;  with  discrete 
succession  right  judgments  exceeded  wrong  at  20o-;  the  time 
order  of  succession  was  caught  with  certainty  at  480-.  Weyer 
found  a  slight  drag  at  i2o-,  a  'flicker'  at  250—300-,  clear  suc- 
cession at  43o"-53o-.     Charpentier  discerned  succession  at  270-. 

In  the  portion  of  the  present  experiments  where  the  vision 
was  direct  and  the  conditions  otherwise  were  most  favorable. 
Observer  S.,  even  with  so  brief  an  interval  as  50-,  distinguished 
succession  from  simultaneity  11  times  in  14  trials  {i.  e.,  80  per 
cent,  of  the  judgments  were  correct;  cf.  Table  VI.,  p.)  277.    B., 

1  See  pp.  263  ff.  of  the  present  paper. 


PERCEPTION  OF  MOVEMENT  281 

when  the  interval  was  lOa,  correctly  made  this  distinction  in  10 
of  the  14  cases  offered  him  (70  per  cent.;  cf.  Table  III.,  p.  275, 
and  Table  V.,  p.  276,  where  two  thirds  of  B.'s  answers  were  cor- 
rect, with  I0(t).  And,  again,  with  indirect  vision,  an  interval  of 
but  50-  still  permitted  Observer  S.  to  give  correct  judgments 
regarding  discrete  succession  in  9  cases  out  of  12  (75  per  cent.; 
cf.  Table  X.,  above. 

Such  a  lowering  of  the  time-threshold  to  about  one  third 
of  what  usually  has  been  considered  its  lowest  value  (to  50-, 
as  against  150-),  if  motion  be  regarded  as  offering  the  finest 
measure  of  the  time-threshold;  or  to  about  one  ninth  of  its 
accepted  value  (to  50-,  as  against  450-)  if  succession  be  taken 
as  criterion, — this  lowering  is  to  be  ascribed  to  a  combination 
of  causes:  perhaps  (i)  to  the  method  of  presentation,  inas- 
much as  examples  both  of  simultaneity  and  of  non-simul- 
taneity, it  was  known,  would  be  offered,  and  the  observer  had 
simply  to  affirm  which  was  which;  and  (2)  to  the  instru- 
mental arrangement, — whereby  there  was  given  an  immediate 
juxtaposition  of  successive  lights,  yet  without  fusion — an 
arrangement  analogous  to  the  successful  'vernier-method'  in 
experiments  with  space;  and  (3)  to  practice,  since  with  each 
subject  a  far  greater  number  of  experiments  was  completed 
than  has  been  usual  in  this  field. 

Some  might  feel  tempted  to  say  that  the  lowering  of  the 
values  arose  from  the  fact  that  the  judgments  here  given 
were  not  due  in  the  first  instance  to  time-perception  at  all; 
that  they  were  time-judgments,  but  derived  from  an  appear- 
ance not  primarily  temporal — derived  perhaps  from  intensive 
differences  in  the  light  at  the  point  of  junction  of  the  two 
halves  of  the  slit.  I  have  myself  tried  impartially  to  enter- 
tain a  supposition  of  this  kind,  but  after  serving  long  as  an 
observer  in  the  experiment  the  phenomenon  has  seemed  too 
me  clearly  a  time-phenomenon;  has  seemed  to  be  the  con- 
scious presence  or  absence  of  precise  and  punctual  synchro- 
nousness  in  the  luminous  slit.  There  appeared  to  me  no 
intensive  difference  between  a  pair  of  lights  that  were  exactly 
simultaneous  and  a  pair  in  which  succession  was  just  dis- 
cernible; nor  is  it  probable,  although  still  conceivable,  that 
such  a  difference  was  there. 


282 


G.  M.  STRATTON 


Optimal  Orders  or  Directions. — To  one  other  aspect  of  the 
observers'  judgments  attention  might  be  called, — namely  to 
an  occasional  partiality  which  the  observers  had  for  a  par- 
ticular order  of  succession,  a  particular  direction  of  movement. 
If  we  segregate  the  judgments  passed  upon  a  succession 
actually  'above-below,'  and  again  the  judgments  passed  upon 
a  succession  actually  'below-above';  and  likewise  with  motion 
downward  and  motion  upward,  we  obtain  the  values  set 
forth  in  Tables  XI.  and  XII. 

Table  XI 

Observer  B 
Segregation  of  Different  Orders  and  Directions 


Succession 

Motion 

Time 

Above-below 

Below-above 

Downward 

Upward 

Suc- 
cesses 

Fail- 
ures 

Suc- 
cesses 

Fail- 
ures 

Suc- 
cesses 

Fail- 
ures 

Suc- 
cesses 

Fail- 
ures 

300- 
2S<r 
20<r 

IOC- 

6 
6 
7 
4 
6 

3 

0 
0 
0 

3 

I 

4 

6 
6 
6 
6 
4 
3 

0 
0 
I 

I 
3 
4 

4 

5 
5 
4 

2 

2 
I 

2 

3 
S 
5 

4 
4 
5 
2 
0 

4 

2 
2 
2 
5 

7 
3 

CO 

■  1"? 

0  B 

Total. 

32 

8 

31 

9 

22 

18 

19 

21 

zoo- 
ISO- 
IOC- 

6 
S 
4 
3 

0 
I 

2 
3 

5 
5 
4 
3 

I 
I 
2 
3 

2 
5 
4 
0 

4 
I 

2 
6 

5 
3 
4 
4 

I 

3 
2 
2 

Presenta- 
tion in 
pairs— di- 
rect vis- 
ion. 

Total. 

18 

6 

17 

7 

II 

13 

16 

8 

300- 
2S(r 

ZOiT 

5 
4 
3 
4 

I 

2 

3 
2 

6 
4 
3 
4 

0 

2 

3 

2 

5 
5 
2 
2 

I 

I 
4 
4 

5 
5 
4 
6 

I 

I 
2 
0 

Presenta- 
tion in 
pairs— in- 
direct vis- 
ion. 

Total. 

16 

8 

17 

7 

14 

10 

20 

4 

Grand  total. 

66 

22 

65 

23 

47 

41 

55 

33 

In  Table  XII.  (Observer  S.)  it  will  be  noticed  that  with 
succession,  when  the  order  is  above-below  the  total  number  of 
successes  is  81,  as  against  63,  when  the  order  is  reversed 
(below-above);  and  likewise  with  motion,  when  direction  is 
downward  the  successes  are  74,  as  against  58  when  the  direc- 
tion is  reversed.     And  this  relation  that  appears  in  the  grand 


PERCEPTION  OF  MOVEMENT 

Table  XII 

Observer  S 
Segregation   of  Different  Orders   and  Directions 


283 


Succession 

Motion 

Time 

Above-below 

Below-above 

Downward 

Upward 

Suc- 
cesses 

Fail- 
ures 

Suc- 
cesses 

Fail- 
ures 

Suc- 
cesses 

Fail- 
ures 

Suc- 
cesses 

Fail- 
ures 

300- 
250- 
200- 

I5<T 
I  Off 

5 
6 
6 
6 
5 
4 

I 

0 
0 
0 
I 

2 

5 
5 
6 

3 
0 

2 

I 
I 
0 

3 
6 

4 

6 

5 
6 
6 
4 
3 

0 
I 

0 
0 

2 

3 

6 
4 
4 

5 
3 
3 

0 

2 
2 
I 

3 
3 

CO 

5-1  S 
3  '  n 

•  a.0 

Total. 

32 

4 

21 

IS 

30 

6 

25 

II 

20ff 

lOcr 
5*^ 

7 
6 
6 
6 

0 
I 

I 
I 

7 
4 

5 
5 

0 

3 
2 
2 

6 
7 
5 
4 

I 

0 

2 
3 

7 
6 

2 
2 

0 

I 
5 
5 

Presenta- 
tion by 
pairs— di- 
rect    vis- 
ion. 

Total. 

25 

3 

21 

7 

22 

6 

17 

II 

3  Off 
2Sff 
20ff 

I  Off 

5<^ 

2 
2 
5 
4 
6 

5 

0 
0 

I 
2 
0 

I 

2 
I 
6 
S 
3 
4 

0 

I 
0 

I 

3 
2 

2 
2 
6 

S 
5 
2 

0 
0 
0 
I 

I 
4 

2 
2 

5 
4 

I 
2 

0 
0 
I 

2 
5 
4 

i?-  £ 

0*0  3 

•■J  -1  !!i 

O-I.B 
B  3 

Total. 

24 

4 

21 

7 

22 

6 

16 

12 

Grand  total. 

81 

II 

63 

29 

74 

18 

58 

34 

totals  also  appears  In  the  sub-totals  obtained  by  each  separate 
method  and  region  of  the  retina;  there  is  invariably  greater 
success  with  the  order  'above-below,'  invariably  greater 
success  with  the  direction  downward. 

In  Table  XL  (Observer  B.),  the  partiality  is  exceedingly 
faint,  if  not  entirely  absent;  certainly  absent  when  succession 
is  being  offered,  for  here  the  total  number  of  right  judgments 
when  the  order  is  'above-below'  is  almost  exactly  the  same 
as  with  the  reverse  order  (66  as  against  65)  ,and  the  sub-totals 
show  a  like  approximation.  But  with  motion  there  is  perhaps 
a  slight  partiality  for  the  upward  direction  (55  successes  as 
against  47  with  motion  downward), — a  partiality,  however, 
so  phlegmatic  that  a  mere  change  of  method  from  double  to 
single  presentation  is  sufficient  to  reverse  it. 


2S4 


G.  M.  ST  R  ATT  ON 


Nor  is  the  partiality  confined  to  diflFerences  in  vertical 
direction;  it  appears  in  experiments  with  the  horizontal  direc- 
tion as  well.  With  Observer  S.,  in  whom  the  difference  in 
result  for  the  different  orders  of  appearance  was  most  pro- 
nounced, supplemental  experiments  were  tried  in  which  the 
stationary  slit  {i.  <?.,  the  slit  upon  the  front  screen)  lay  in  a 
horizontal  instead  of  a  vertical  position,  and  with  the  rest 
of  the  apparatus  so  adjusted  as  to  give  illuminations  of  the 
two  halves  of  the  slit  in  the  order  'left-right,'  as  well  as  in 
the  order  'right-left.'  And  also  (to  answer  the  question 
whether  the  advantage  might  in  any  way  be  due  to  the  fact 
that  the  stationary  slit  was  a  parallelogram  and  so  permitted 
the  half  of  the  illumination  that  came  from  that  portion  of 
the  radial  slit  lying  nearer  the  center  of  the  wheel  to  appear 
an  almost  infinitesimally  longer  period  than  the  illumination 
from  the  more  distant  portion),  experiments  were  performed 
with  two  different  characters  of  stationary  slit, — in  the  one 
case,  as  hitherto,  with  sides  exactly  parallel;  in  the  other  case, 
with  sides  slightly  departing  from  this  arrangement,  so  that, 

Table  XIII 

Observer    S.     Direct    Vision,    Pair    Presentation,    Horizontal    Direction 

Succession 


Time 

I,eft-right 

Right-left 

Successes 

Failures 

Successes 

Failures 

\0<T 

5<^ 

II 

6 

I 
18 

12 
19 

0 

5 

With  paral- 
lelogram slit. 

17 

19 

31 

5 

IOC- 

9 
6 

3 
6 

12 

12 

0 
0 

With      radial 
slit. 

IS 

9 

24 

0 

Total. 

32 

28 

55 

5 

had  they  been  extended,  they  would  have  met  at  the  center 
of  the  wheel  (t.  e.,  a  radial  slit  instead  of  a  narrow  parallel- 
ogram). Thus  both  halves  of  the  slit  gave  absolutely  equal 
durations  of  illumination.  In  all  other  respects  the  pro- 
cedure was  unchanged.  Table  XIII.  shows  the  outcome  of 
these  experiments. 


PERCEPTION  OF  MOVEMENT 


285 


The  advantage,  which  with  the  vertical  slit  was  for  the 
order  'above-below,'  here  reappears  strong,  and  for  the  order 
*  right-left.'  Out  of  60  trials  with  this  particular  order,  but 
5  errors  were  made;  whereas  for  a  like  number  of  trials  with 
the  opposite  order  28  errors  were  made. 

These  partialities  had  already  been  noticed,  as  I  have  said, 
in  the  earlier  experiments,  with  the  pendulum;  and  in  Table 
XIV.  they  are  set  forth  in  conjunction  with  those  found  in 
the  later  experiments. 

Table  XIV 

Unconscious  Partialities  for  Particular  Orders  and  Directions 

(/.  I?.,  the  order  or  direction  in  which  there  was  heightened  facility,  or  lowered 
threshold.) 


I  In  Case  of  Succession 

In  Case  of  Motion 

Observer 

Earlier  Experi- 
ments (Pendulum) 

I,ater  Experi- 
ments (Wheel) 

Earlier  Experi- 
ments (Pendulum) 

I,ater  Experi- 
ments (Wheel) 

B 

S 

above-below 

(slight) 
above-below 

no  preference 

above-below 
right-left 

upward 
downward 

upward  (slight) 
downward 

The  suspicion  with  which  I  closed  the  earlier  set  of  experi- 
ments, that  such  partiality  was  a  mere  appearance  due  to 
some  aberration  in  the  apparatus^  was  thus  evidently  un- 
warranted. The  unequal  facility  of  dealing  with  the  rival 
orders  and  rival  directions  reappears  in  the  later  experiments 
and  in  the  same  general  sense:  the  preference  for  upward 
motion  in  the  earlier  experiments  in  answered  by  a  preference 
for  the  upward  motion  in  the  later;  the  preference  for  the 
succession  'above-below'  is  answered  by  a  preference  for 
this  same  succession.  Only  in  B.,  in  whom  the  tendency 
is  weak  at  best,  the  partiality  grows  less  in  the  later  experi- 
ments, passing  away  entirely  in  the  case  of  succession.  It 
is  thus  an  individual  matter;  for  the  different  observers  do 
not  agree  in  their  partialities;  and  of  course  it  is  not  to  be 
regarded  as  a  conscious  liking.  No  observer  expressed  any 
preference  for  an  order  or  a  direction.  By  'partiality'  is 
meant,  then,  no  emotional  difference,  but  merely  a  greater 

^See  p.  272. 


2S6  G.  M.  STRATTON 

ability  of  perception  or  of  discrimination.  It  seems  to  have 
some  similarity  (though  I  can  hardly  believe  that  there  is 
any  causal  connection  between  the  two)  to  the  greater 
aptitude  for  detecting  a  departure  from  linear  continuity 
when  the  departure  was  upon  the  right,  racher  than  upon  the 
left,  of  the  standard  vertical;^  or  to  the  personal  differences 
in  dealing  with  successive  shocks  and  successive  clicks  which 
others  have  found, ^  In  explanation  of  the  partialities  appear- 
ing in  the  present  experiments,  I  feel  tempted  to  believe  that 
they  may  be  due  to  certain  obscure  habits  or  tricks  of  atten- 
tion. It  is  probable  that,  other  things  equal,  some  persons 
are  slightly  more  ready  to  attend  to  an  object  in  the  upper 
half  of  the  visual  field  than  in  the  lower;  while  with  the  others 
the  reverse  may  be  true.  One  whose  attention  had  any  such 
inclination  would  seem  to  have  the  foundation  for  a  partiality 
like  that  of  the  present  experiment.  It  is  significant,  in  this 
connection,  that  with  S.,  the  advantage  which  a  particular 
order  of  succession  holds  is  shared  by  the  corresponding 
direction  of  motion.  With  B.,  however,  this  is  not  true, 
at  the  very  time  when  succession  in  the  order  'above-below* 
had  an  advantage,  the  advantage  in  the  region  of  motion 
lay  with  the  direction  opposed  to  this,  lay  namely  with  motion 
upward. 

V.   The  Precise  Relation  between  Succession  and 

Motion 
Turning  now  to  the  main  question,  which  serves  as  a  title 
to  this  paper,  I  believe  we  shall  be  more  likely  to  succeed  in 
answering  it  if  we  divide  and  attend  to  each  division  sepa- 
rately, (i)  Is  the  consciousness  of  rapid  motion  (such  as 
we  have  had  in  these  experiments)  intimately  bound  up  with 
the  consciousness  of  succession;  or  are  they  distinct  and  even 
independent  mental  processes.?  (2)  Are  these  mental  proc- 
esses, whatever  their  relation  may  be,  rightly  designated  as 
sensations?     These  are  separate  questions,  although   the   an- 

^See  'A  New  Determination  of  the  Minimum  Visibile,'  etc.,  Psychological 
Review,  VII.,  429;  and  'Visible  Motion  and  the  Space  Threshold,'  Psychological 
Review,  IX.,  433. 

^Hamlin,/On  the  Least  Observable  Interval,'  etc.,  Amer.  Journ.  of  Psychol.,  VI. 
564  ff.     Drew,  'Attention,'  Amer.  Journ.  of  Psychol.,  VII.,  533  ff. 


PERCEPTION  OF  MOVEMENT  ^S*/ 

swer  to  one  may  involve  or  determine  the  answer  to  the  other. 

In  answer  to  the  preceding  of  these  questions,  one  may 
speak  first  in  negatives.  I  am  inclined  to  believe  that  the 
facts  brought  out  by  the  present  experiments,  in  conjunction 
with  what  has  been  done  before,  very  nearly  annul  the  sup- 
posed evidence  for  the  independence  of  succession  and  motion; 
at  least  so  far  as  the  claim  for  the  priority  of  motion  is  con- 
cerned. For  it  is  now  apparent  that  the  detection  of  motion 
is  nicer  than  that  of  discrete  succession  neither  on  the  spatial 
side  nor  yet  upon  the  temporal.  Motion  cannot  be  discerned 
within  space-limits  too  small  for  discriminating  positions; 
nor  within  time-limits  too  narrow  to  permit  the  conscious 
distinction  of  instants.^ 

On  the  other  hand,  a  certain  claim  might  now  be  set  up 
for  the  priority  of  discrete  sequence.  For  upon  the  whole, 
the  threshold  when  'succession'  was  employed  was  lower  than 
when  there  was  motion.  Moreover  this  meant  not  simply 
that  an  external  and  objective  succession  broke  up  the  appear- 
ance of  simultaneity  more  readily  than  did  motion,  but  that 
the  observers  were  inclined,  under  the  conditions  here  ar- 
ranged, and  with  continued  practice,  to  give  their  judgment 
of  such  non-simultaneity  in  the  form  'sequence'  long  before 
they  were  ready  to  declare  it  to  be  'motion.'  And,  indeed, 
this  seems  to  me  in  keeping  with  what  we  know  from  a  wide 
variety  of  experiments:  in  keeping  with  the  greater  ease  in 
deciding  the  vaguer — the  more  abstract — feature  of  an  im- 
pression; for  the  decision  as  to  the  more  definite,  the  more 
concrete,  characteristics  comes  later  and  with  more  difficulty. 
Since,  in  contradiction  to  Berkeley's  principle,  we  can  tell 
that  a  pressure  has  changed,  far  more  readily  than  we  can 
decide  whether  it  has  become  heavier  or  lighter;^  and  since 

^Nor,  it  might  be  added,  can  motion  be  noticed  at  an  intensity  too  weak  for 
the  detection  of  a  motionless  light.  Contrary  to  a  certain  prejudice  aroused  by  the 
attention  which  moving  objects  so  readily  command,  a  moving  light,  when  attention 
is  full  upon  it,  cannot  be  seen  at  so  low  an  intensity  of  stimulus,  as  can  a  stationary 
light.  Here  again  the  supposed  sensory-advantage  of  motion  proves  ill-claimed.  See 
'Some  Experiments  on  the  Perception  of  the  Movement,  Color,  and  Direction  of 
Lights,'  etc.,  in  the  Johns  Hopkins  Studies  in  Philosophy  and  Psychology,  No.  2,  pp.  88  f. 

2  See  'Ueber  die  Wahrnehmung  von  Druckanderungen,'  etc.,  in  Wundt's  Philos. 
Studien,  XII.,  534  ff.,  539. 


288  G.  M.  STRATTON 

we  show  a  like  tendency  in  many  other  fields;  it  would  not 
be  surprising  if,  at  bottom,  it  were  easier  to  decide  that 
simultaneity  had  in  some  general  way  been  violated, — that 
the  impression  was  in  some  vague  form  successive, — perhaps 
even  without  being  of  a  succession  distinctly  discrete — than  to 
decide  whether  it  was  succession  plus  those  special  and  par- 
ticular marks  of  continuity  both  in  space  and  time  that  char- 
acterize motion.  Succession  means  merely  change;  discrete 
succession  means  change  with  some  temporal  interim  or 
cessation  of  the  process,  motion  means  that  the  change  has 
no  such  temporal  interim,  and  furthermore  that  there  is 
perfect  continuity,  along  with  shift,  in  the  space  involved. 
But  such  an  account  implies  some  weakening  of  the  claim  to 
priority  on  the  part  of  discrete  succession;  for  this  is  almost, 
though  not  quite,  as  advanced  a  specification  of  succession 
as  motion  is. 

The  positive  side  of  the  answer  to  the  question  as  to  the 
relation  of  sequence  and  motion  would  therefore  seem  to  me 
to  be  this:  that  motion  involves  as  a  constituent  element 
sequence  although  not  discrete  sequence;  the  rather  it  in- 
volves sequence  particularized  in  a  way  soon  to  be  described; 
but  in  any  event,  that  motion  is  the  more  special  and  ad- 
vanced form  of  the  sequence-consciousness.  Yet  it  is  the 
one  to  which  the  mind  rushes  headlong.  For  just  as  in  our 
perception  we  hasten  to  fill  out  the  lacunae  of  impression, 
even  at  the  risk  of  illusion;  just  as  it  is,  in  one  sense,  far 
easier  to  see  as  a  man  the  form  and  color  which  a  human  being 
offers  to  the  eye  and  color;  and  yet  this  interpretation,  while 
most  difficult  to  suppress,  is  an  advance  and  addition  to  the 
consciousness  of  mere  form  and  color — so  with  motion.  The 
rapid  sensory  sequences  which  nature  offers  us  in  any  one 
region  of  space  are  predominantly  continuous  sequences — 
continuous  in  both  space  and  time;  the  flutter  of  leaves  and 
of  grass,  the  darting  of  birds  and  of  insects,  the  quick  action 
of  eyes  and  lips  and  fingers  in  men  about  us.  And  so  the 
mind  becomes  accustomed  to  this  manner  of  interpreting  all 
rapid  change;  it  interprets  it  instinctively  as  motion.      But 


PERCEPTION  OF  MOVEMENT  289 

this  precipitancy  of  nterpretation  should  deceive  the  psy- 
chological analyst  no  more  in  the  one  case  than  in  the  other.  As 
little  as  we  should  now  be  inclined  to  say  that  the  perception 
of  a  cow  is  independent  of  the  consciousness  of  extensity, 
although  most  of  us  see  cows  in  a  field  more  readily  than  red- 
extensities  there;  so  little  in  the  end  will  we  be  inclined  to 
regard  motion,  for  all  its  greater  readiness  to  arise  in  the 
mind,  as  independent  of  sequence  or  succession.  Motion  is 
different  from  sequence,  whether  discrete  or  continuous,  but 
only  inasmuch  as  it  Is  sequence  made  specific,  made  more 
concrete  by  giving  it  a  peculiar  spatial  character.  The  rela- 
tion of  those  processes,  so  far  as  complexity  and  dependence 
is  concerned,  might  be  illustrated  by  the  accompanying 
diagram. 

Some  Temporal  Connection 


Simultaneity  Sequence 

Discrete  Succession      j  Continuous  Succession 


Unbroken  change  other  Unbroken  change  of  place 

than  that  of  place  (motion) 

When  the  mind  is  not  on  its  guard,  it  rushes,  on  the  slightest 
excuse,  through  all  the  intermediate  stages  to  a  conviction 
of  movement.  In  that  sense,  the  motion-interpretation  Is 
simpler;  It  Is  more  natural,  it  is  the  course  in  which  experience 
has  drilled  us.  But  the  mind  needs  a  more  intense  stimula- 
tion, it  requires  an  Impression  whose  diiferential  marks  are 
more  pronounced,  if  the  mind  is  to  be,  not  merely  more 
confident,  but  actually  more  accurate  in  detecting  the  real 
character  of  the  change  presented  to  it.  Practiced  observers 
therefore  when  confronted  with  faint  changes  such  as  occurred 
in  these  experiments  unwittingly  fall  back,  sooner  or  later, 
on  the  less  commital  form  of  judgment — that  of  'succession' 
merely;  passing  on  to  the  farther  specification, — the  judg- 
ment that  the  succession  Is  actually  of  'motion' — only  when 
the  Impression  has  become  more  clear.  They  have  become 
schooled  out  of  their  impulsive  readiness  to  take  all  rapid 


290  G.  M.  STRATTON 

visual  change  (unless  there  are  unmistakable  signs  to  the 
contrary)  as  movement.^ 

But  the  fact  that,  on  the  whole,  my  observers  reserved 
the  judgment  'movement'  for  the  more  pronounced  and 
definite  stimulations,  and  usually  formed  only  the  vaguer 
judgment  'sequence'  or  'succession'  or  'some  departure  from 
simultaneity,'  when  the  impression  was  approaching  its 
liminal  value, — this  does  not  touch  the  farther  question  as 
to  what  form  of  stimulus  will  best  furnish  the  definiteness  of 
impression  that  permits  even  the  vaguer  judgment  to  be 
passed  reliably.  It  would  seem  from  the  present  experiments 
that  with  trained  observers  discrete  succession  customarily 
gives  a  much  greater  shock,  a  less  mistakable  violation  of 
simultaneity,  than  does  continuous  succession  (motion).  A 
less  time  suffices  to  make  discrete  succession  seem  non- 
simultaneous,  than  is  required  to  make  motion  distinct  from 
simultaneity.  At  times  this  is  not  so;  the  just-perceptible 
violation  of  simultaneity  comes  equally  well  from  either 
source.  But  the  other  relation  is  perhaps  the  rule.  Indeed, 
this  would  seem  in  keeping  with  the  general  intensification 
and  shock  and  start  which  interruptions  give,  and  the  greater 
ease  and  smoothness  of  continuous  change. 

To  sum  up  then  the  answer  to  the  first  of  our  questions. 
Whether  the  consciousness  of  rapid  motion  is  intimately 
bound  up  with  the  consciousness  of  succession,  or  is  inde- 
pendent; it  is  this:  that  the  two  are  intimately  conjoined^  the 
judgment  of  motion  being  a  farther  specification  {more  complex^ 
and  yet  easier)  of  the  judgment  of  sequence.  The  judgment  of 
motion  has  a  certain  priority,  in  the  sense  that  it  is  both  more 
complex  and  also  more  readily  performed,  much  as  the  move- 
ment of  four  fingers  of  a  hand  is  easier,  though  more  complex, 
than  the  movement  of  one  finger  alone.  The  judgment  of 
succession,  however,  has  its  own  priority,  inasmuch  as  it  is  the 
simpler,  and  requires  a  less  lasting  stimulation  to  evoke  it. 

And  the  answer  to  this  first  question  has  perhaps  already 

^This  naive  readiness  is  well  seen  in  the  almost  inevitable  impression  of  'winking' 
which  a  rapid  intermission  of  light  produces.  The  twinkling  of  stars  with  its  sense 
of  motion  is,  I  doubt  not,  three  fourths  motion-illusion  due  to  rapid  intensive  change, 
the  other  fourth  the  actual  shift  that  the  light  undergoes  by  changes  of  refraction. 


PERCEPTION  OF  MOVEMENT  291 

suggested  the  answer  I  feel  bound  to  give  to  the  second, — 
the  question  whether  the  consciousness  of  succession  or  of 
movement  (even  when  rapid)  is  to  be  designated  as  sensation. 
In  dealing  here  with  out  consciousness  of  succession  and  of 
movement  the  expression  'judgment'  has  often  been  em- 
ployed; and  yet  there  is  hardly  any  need  of  warning  that 
the  core-substance  of  succession  or  of  motion,  as  they  here 
appear,  is  not  a  mere  judgment,  but  has  a  strong  admixture 
of  sensation.  We  see  the  succession,  we  see  the  movement, 
whatever  judgments  we  may  pass  upon  it.  But  Inasmuch  as 
the  conscious  succession,  the  conscious  movement,  involves  a 
certain  relating  and  interpreting  (as  I  have  attempted  to 
indicate,  especially  in  regard  to  motion),  it  would  seem  prefer- 
able— if  one  were  to  limit  himself  to  the  usual  alternatives-^ 
to  regard  it  as  a  perception,  rather  than  as  either  a  sensation  or  a 
judgment.  The  sensory  impression  is  here  grasped  in  its  simple 
relations  of  time,  it  is  here  interpreted  and  felt  to  belong  to 
a  certain  familiar  type  of  experience.  And  just  as  we  speak 
of  the  perception  of  a  cow,  and  the  sensation  of  red;  so  too 
in  principle  (though  now  the  span  between  the  bare  impression 
and  Its  'form'  or  'system'  is  almost  too  small  for  observation) 
we  must  distinguish  the  perception  of  succession  (or  the  per- 
ception of  motion)  from  the  sensations  which  are  its  in- 
gredients and  sign.  The  term  'sensation,'  I  take  it,  desig- 
nates a  sheer  abstraction,  designates  the  'matter'  of  sensory 
impressions  as  distinguished  from  their  'form.'  If  then  the 
peculiar  meaning  of  sensation  and  its  distinction  from  per- 
ception (as  a  consciously  formed  or  organized  Impression) 
is  to  be  preserved,  it  seems  best  to  regard  the  conscious  process 
with  which  we  have  here  been  so  long  dealing  as  a  perception 
or  percept,  rather  than  as  a  sensation. 

Yet  perhaps  the  negative  side  of  the  argument — that  these 
processes  are  not  mere  sensations — Is  perhaps  more  convincing 
than  the  positive  side,  which  urges  that  they  be  called  'per- 
ceptions.' For  the  term  'perception'  covers  an  Idea  that 
must  in  time  be  resurveyed  and  subdivided.  We  are  sadly  in 
need  of  a  more  precise  expression  here,  and  were  it  not  for  a 
natural  hesitation  at  new  terms,  one  would  feel  tempted  to 


Onlwtslly  (if  Callfomla 


292  G.  M.  STRATTON 

propose  that  (since  no  external  object  is  here  'received'  or 
'taken'  through  the  sense,  or  the  sensation, — which  is  a 
prominent  element  in  at  least  the  earlier  idea  of  perception) 
we  designate  these  simple  organizations  of  sensory  'matter' 
where  no  physical  'thing'  is  caught,  as  'infra-percepts,' 
or  'aesthamorphs.'  For  there  is  here  the  need  of  marking  a 
stage  where  sensation  has  been  organized,  yet  not  organized 
into  a  perceptive  object  or  thing. 

Summary 

1.  When  successive  lights  are  exactly  juxtaposed  spatially, 
motion  that  is  just  perceived  does  not  occupy  a  briefer  time 
than  mere  succession  that  is  just  perceived. 

2.  On  the  contrary,  practiced  observers  can  usually  per- 
ceive mere  succession  whose  time-limits  are  less  than  those  of 
just-noticeable  motion. 

3.  And  the  judgment  of  such  observers  more  readily  takes 
a  form  affirming  mere  non-simultaneity  rather  than  motion. 

4.  Under  the  conditions  here  arranged,  a  succession  of 
lights  but  50-  apart  could  be  discerned  by  the  writer  in  80  per 
cent,  of  the  trials, — and  the  other  observer  also  detected 
succession  considerably  below  the  limits  hitherto  accepted  as 
obtaining  in  this  region, 

5.  For  each  person,  there  is  usually  an  optimal  direction 
of  succession  or  of  movement.  That  is,  a  succession  or  move- 
ment in  the  order  above-below  (or  the  reverse)  may  be  noticed 
at  a  rate  at  which  the  succession  or  motion  in  the  opposite 
direction  is  quite  imperceptible.  This  preferred  order  is  not 
the  same  for  all  persons,  and  in  the  same  individual  the  pre- 
ferred order  for  succession  need  not  be  the  preferred  order 
for  motion. 

6.  The  general  relations  described  above  appear  to  obtain 
in  eccentric  as  well  as  in  foveal  vision,  although  the  absolute 
values  in  the  two  regions  may  differ. 

7.  A  change  of  method  from  that  of  single  presentations 
to  the  method  of  paired  presentations  generally  brings  about 
both  a  nicer  and  a  more  constant  recognition  of  the  phenome- 
non offered. 


PERCEPTION  OF  MOVEMENT  293 

8.  The  relation  between  the  consciousness  of  succession 
and  that  of  motion  Is  exceedingly  Intricate.  The  conscious- 
ness of  motion  is  a  farther  'specification'  of  the  consciousness 
of  succession,  somewhat  as  the  consciousness  of  Increase  or 
decrease  of  pressure  is  a  farther  specification  of  the  conscious- 
ness of  mere  change  of  pressure.  The  two  orders  of  percep- 
tion are  certainly  distinct,  although  quite  as  certainly  not 
independent,  since  the  more  specific  apprehension  always  in- 
volves the  less  specific,  but  not  vice  versa.  The  seeing  of 
motion  Is  a  more  elaborate,  and  yet  at  the  same  time  more 
facile  mental  act,  than  the  seeing  of  mere  succession.  The 
headlong  readiness  to  interpret  all  neighboring  successions 
as  motions,  to  which  the  world  has  trained  the  mind,  can 
however  be  checked  by  special  and  cautious  observation,  and 
then  the  essentially  simpler  judgment  or  perception,  that  of 
mere  succession,  is  the  one  that  more  readily  arises. 

9.  The  consciousness  of  rapid  motion  or  of  rapid  succession 
is  not  a  mere  sensation,  nor  Is  it  a  mere  judgment,  nor  again 
is  It  a  perception  In  the  older  historic  meaning  of  the  term. 
It  is  rather  a  sensation  or  group  of  sensations  consciously 
organized,  and  yet  not  organized  into  anything  so  concrete 
as  a  'thing'  or  a  substantial  object.  It  therefore  lies  some- 
where between  sensation  and  perception,  and  seems  to  call 
for  a  special  designation, — perhaps  'infra-percepts'  or  'aestha- 
morphs.' 


STUDIES   FROM  THE   PSYCHOLOGICAL  LABOR- 
ATORY OF  THE   UNIVERSITY 
OF   CALIFORNIA 

XVI.     Temporal  and  Accentual  Rhythm 


BY  WARNER  BROWN 


Reprinted  from  the  Psychologicai,  Review,  September,  191 1, 
Vol.  XVIII,  No.  5. 


[Reprinted  from  The  Psychological  Review,  Vol.  XVIII.,  No.  5,  Sept.,  1911.] 


STUDIES   FROM  THE   PSYCHOLOGICAL  LABOR- 
ATORY  OF  THE   UNIVERSITY 
OF   CALIFORNIA 

XVI.     Temporal  and  Accentual  Rhythm 

BY  WARNER  BROWN 

Perhaps  the  only  undisputed  characteristic  of  rhythm  is 
the  impression  of  regularity  which  it  occasions.  Some  hold 
that  this  impression  arises  from  the  regular  recurrence,  in 
time,  of  certain  features  of  the  rhythmic  series;  others  claim 
that  the  regularity  resides  in  the  structure  of  the  elements 
composing  the  series;  but  in  either  case  some  regularity  is 
admitted.  A  rhythm  lacking  regularity  in  its  structure  and 
failing  in  the  regular  repetition  of  its  elements  would  be  no 
rhythm. 

I 

The  mere  repetition  of  a  single  undifferentiated  movement 
or  sound  does  not  constitute  a  rhythmic  series,  properly  speak- 
ing, and  yet  such  a  series  offers  one  of  the  most  satisfactory 
approaches  to  the  more  truly  rhythmic  forms.  Movements 
either  with  the  voice  or  by  tapping,  are  easily  recorded  by 
the  kymograph,  and  may  be  measured  and  studied  at  leisure. 
On  that  account  a  series  of  movements  can  be  analyzed  to 
better  advantage  than  a  series  of  sounds. 


L 


^0ttftt0^f^^^r^m^m0^tm0^0^0^0t0^^^0^*^^^^f*m^^^0^^*^^^»^^^^^*^*^^^*^*^^*^*^^^*^^*^*^'^'^^^'^*^*^^*^^'^*^'^^'^ 


]}J,cxaJIou\,         LclJz^ 


Fig.  I. 


Fig.  I  shows  a  series  of  regular  taps  made  by  the  finger. 
Here  regularity  is  the  dominant  characteristic.  But  regu- 
larity  is   seen   to   be   of  two   distinct   sorts.     Regularity   of 

336      . 


337  WARNER  BROWN 

recurrence  appears  in  the  duration  of  the  taps  and  the  interval 
between  them,  and  over  against  this  is  regularity  in  the 
performance  itself,  which  manifests  itself  in  the  force  of  the 
movement.  In  the  record  the  duration  is  measured  hori- 
zontally and  the  force  vertically.     The  degree  of  regularity 

Table  I 

Regular  Taps 
Showing,  for  each  Subject,  the  Mean  Variation,  in  per  cent.,  from  the  average  of 
20  taps;  with  regard  to  the  Force  and  Duration  of  the  taps. 

Subject  Force  Duration 

1.  Mr.  Bates 6.22  3.42 

2.  Mr.  Detter 9.02  6.44 

3.  Mr.  Dignan 5.78  2.66 

4.  Miss  Fisher 11.79  2.40 

5.  Mr.  Folte 16.90  4.28 

6.  Mr.  Ham 5.90  3.12 

7.  Miss  Hendee 10.80  5.69 

8.  Mr.  Jackson 8.68  3.81 

9.  Miss  Noteware 6.78  3.03 

10.  Mr.  Robinson 5.94  3.37 

11.  Miss  Replogle 15.50  10.00 

12.  Mrs.  Stanley 13.60  3.31 

13.  Miss  Umphred 11.90  3.50 

14.  Miss  Way 10.95  4.38 

15.  Mr.  Whisman 5.92  4.99 

Average 9.71  4.36 

is  found  by  computing  the  mean  variation  from  the  average 
of  a  number  of  successive  movements.^  Table  I.  shows  the 
variation  in  force  and  duration  of  a  series  of  twenty  taps 
with  the  index  finger  on  the  rubber  head  of  a  drum  connected 
with  a  recording  tambour.  The  subjects^  were  requested  to 
tap  as  regularly  as  possible  in  time  and  force  and  at  a  rate 
of  their  own  choosing.  On  the  whole,  averaging  the  records 
of  the  subjects,  these  taps  vary  more  than  twice  as  much  in 
force  as  in  time.  In  other  words  their  duration  is  more  than 
twice  as  regular  as  their  structural  form.     For  some  persons 

^  The  measurements  of  the  movements  themselves  are  of  no  importance  in  the 
present  connection,  and  for  the  sake  of  clearness  only  the  variations  from  their  average 
are  mentioned.  Throughout  this  paper  the  mean  variation  is  expressed  in  per  cent. 
of  the  quantity  which  varies. 

*  I  am  indebted  to  fifteen  of  my  students  in  the  University  of  California  summer 
session  of  1910  for  the  records  upon  which  this  report  is  based. 


TEMPORAL  AND  ACCENTUAL  RHYTHM  33^ 

the  variation  in  time  is  more  nearly  equal  to  that  in  force, 
but  in  no  case  is  there  less  variation  in  force  than  in  time. 

It  is  evident  that  this  series  tends  to  conserve  a  regular 
succession  of  its  elements  rather  than  regularity  in  their  form. 
But  this  sacrifice  of  form  to  duration  occurs  in  a  series  which 
does  not  profess  to  have  much  form,  and  the  further  question 
arises  whether  the  same  thing  would  hold  in  a  truly  rhythmic 
series. 

II 

Fig.  2  shows  a  series  of  taps  in  rhythm.  The  subjects 
were  instructed  to  tap  in  a  natural  manner  in  an  iambic 
rhythm,  and  the  explanation  was  made  that  this  rhythm  has 
the  second  beat  accented  or  longer  than  the  first,  but  no 


tflft^.-^u.^>ut      Xa^Ak^ 


Fig.  2. 

indication  was  given  as  to  the  relative  importance  of  the 
temporal  or  accentual  features.  Table  II.  shows  for  the 
fifteen  subjects  the  variation  in  force  and  duration  of  the 
first  (short)  and  second  (long)  tap,  based  on  the  average  of 
a  series  of  ten  pairs  of  taps.  The  same  table  shows  the 
variation  in  total  duration  of  the  rhythmic  element  (the  foot, 
or  sum  of  two  successive  taps)  and  of  the  total  force  exerted 
in  the  element  as  measured  by  the  sum  of  the  forces  exerted 
on  the  two  parts  of  it.  This  table  also  gives  a  measure  of 
the  structural  constancy  of  the  elements  in  the  series  both 
in  force  and  time.  This  is  shown  in  the  column  headed 
"ratio"  by  the  variation,  in  the  two  respects,  of  the  ratio 
between  the  two  parts  of  the  foot  when  the  long  or  accented 
part  is  divided  by  the  short  part.^ 

The   more   complicated   performance   demanded   by   this 
part  of  the  experiment  brings  out  more  individual  differences 

1  Again  only  the  variations  are  considered.     Tlie  actual  ratios  will  be  spoken  of 
later  on. 


339  WARNER  BROWN 

Table  II 

Iambic  Taps 
Showing  for  each  Subject  the  Mean  Variation  in  per  cent,  from  the  average  of 
10  pairs  of  taps,  with  regard  to  the  Force  and  Duration  of  the  taps.     The  variation 
is  given  for  the  first  or  Short  tap,  for  the  second  or  Long  tap,  for  the  Sum  of  the  two 
taps,  and  for  the  Ratio  found  by  dividing  the  short  into  the  long  tap. 


Subject 

Short 

I/Ong 

Sum 

Ratio 

F 

D 

F 

D 

F 

D 

F 

D 

I 

2 

3 
4 
5 
6 

7 
8 
9 

ID 

11 
12 

13 
14 
IS 

S-7I 

9.91 

9.17 

12.71 

6.21 

16.32 

15.00 

12.98 

5-28 

7.81 

9-83 
14.60 
11.40 
10.05 

9.14 

5-64 

S-25 
4-S5 
S-I7 
6.22 
4.48 
S-24 
6.32 
4-59 
2-39 
4.02 
4.44 
340 
6.08 
4.48 

1.76 
6.64 
6.02 
9.02 
S-83 
5-49 
7.81 
8.92 
6.18 
S-42 
10.56 
6.54 

7-31 
6.00 
4.78 

5-94 
5-92 
2.60 
3.56 
3-43 
2.66 

6.24 
6.54 
S-70 
4.90 
6.14 
2.19 
4.18 

3-87 
4.25 

2.98 
4.98 
4.02 
10.07 
346 
6.06 

6-43 
4.10 
4.11 
4.68 
6.36 
8.31 
8.31 
3-53 
S-04 

3-31 
4.19 

2.20 
3-34 
4-31 
2.64 

4-54 
3-79 
2.86 

2.35 
5-32 
2.72 
3.20 

4-57 

3.82 

5-32 
14.16 
11.44 
11.83 
II. 41 
19. II 
14.50 
19.38 

6.91 

10.75 
16.42 
12.82 
10.80 
14.60 
10.42 

348 
8.32 

6-35 
6.04 

5-97 
4.62 
5.82 
9.92 
4.68 
6.74 
4.69 
5-17 

7.26 
4.04 

Average. 

10.41 

4.82 

6.55 

4-54 

5-50 

3-54 

12.66 

S-9I 

between  the  subjects,  but  in  the  long  run  and  with  very  few 
exceptions  the  indications  of  the  regular  tap  series  are  borne 
out  by  the  rhythmic  series.  Whether  we  consider  the  short 
initial  stroke,  the  long  accented  stroke,  or  their  sum  (the  whole 
foot),  there  is  greater  variation  in  force  than  in  time.  It 
should  be  noted,  however,  that  except  for  the  initial  stroke, 
there  is  less  difference  between  time  and  force  than  in  the 
case  of  regular  taps.  Taking  the  whole  foot  as  a  basis  for 
comparion  with  the  regular  taps  of  the  first  series  it  is.  seen 
that  the  introduction  of  rhythmic  form  has  tended  to  steady 
the  movements  both  in  time  and  force,  but  has  reduced 
the  variation  in  force  more  than  in  time. 

The  column  headed  'ratio'  (Table  II.)  shows  the  main- 
tenance of  internal  structure  in  the  foot  or  rhythmic  unit. 
On  the  whole  the  temporal  structure  is  maintained  twice  as 
well  as  the  accentual  structure.  In  neither  respect  is  the 
internal  structure  preserved  half  as  well  as  the  uniformity  of 
the  rhythmic  unit;  the  ratios  vary  twice  as  much  as  the  feet. 


TEMPORAL  AND  ACCENTUAL  RHYTHM 


III 


340 


The  third  part  of  the  experiment  (Fig.  3  and  Table  III.) 
reports  a  series  of  syllables  spoken  in  iambic  tetrameter 
rhythm  and  recorded  by  a  tambour  in  the  manner  indicated  in 
an  earlier  paper  of  the  writer's.^  The  subjects  were  instructed 
to  speak,  in  a  natural  rhythm,  the  written  line: 
Ta  ta,  ta  ta,  ta  ta,  ta  ta; 


JZ       ta'    ^tr^      -U     ^     U       "^    y      tl       tl  ^ 


Fig.  3. 


Table  III 

Iambic  Syllables 

Showing  for  each  subject  the  Mean  Variation  in  per  cent,  from  the  average  of 
ten  pairs  of  syllables  from  the  first  foot  of  the  iambic  tetrameter  line  Ta  ta,  ta  ta, 
ta  ta,  ta  ta;  with  regard  to  Force  and  Duration.  The  variation  is  given  for  the  first 
two  syllables  separately,  for  their  Sum,  and  for  the  Ratio  found  by  dividing  the  first 
into  the  second. 


Ta 

ta 

Sum 

Ratio 

Subject 

F 

D 

F 

D 

F 

D 

F 

D 

I 

10.63 

4.14 

12.56 

3-82 

II. 18 

2.76 

5-94 

9-05 

2 

9.22 

4.29 

8.84 

5-27 

6.23 

3.80 

9-79 

5-45 

3 

36.00 

8.85 

18.38 

13.80 

23-40 

9.22 

22.00 

8.32 

4 

40.30 

10.37 

20.30 

7.00 

22.45 

6-33 

43.60 

11.22 

5 

15-92 

7-34 

11.48 

2.96 

11.82 

2-44 

15.60 

8.58 

6 

24.70 

4.42 

30.80 

8.08 

23-50 

3-94 

27.40 

12.65 

7 

13.80 

11.68 

9.14 

6.26 

4.67 

7.10 

22.10 

8.13 

8 

13.60 

7.04 

12.50 

5-Si 

11.80 

4.90 

12.63 

5.76 

9 

28.00 

6.55 

19.50 

4-77 

17.00 

4.06 

24.70 

8.^2 

ID 

16.77 

7-23 

15-43 

12.51 

15-25 

8.22 

20.50 

15.18 

II 

15-30 

10.90 

16.40 

8.27 

15-50 

4-39 

9.68 

16.65 

12 

13-55 

5-67 

26.84 

7.00 

17.00 

5-57 

22.10 

5.81 

13 

34-9° 

21.40 

37-20 

11.24 

25-30 

5-39 

43-70 

28.30 

14 

17-93 

11.00 

16.82 

6.81 

14.50 

5-97 

22.40 

8.23 

IS 

25.80 

6.63 

11-53 

4-13 

15-43 

4.41 

23.50 

10.76 

Average. 

21.09 

8.50 

17.81 

7.16 

15-67 

5-23 

21.71 

10.84 

like  a  line  of  verse,  and  then  to  repeat  the  same  line  as  another 
verse  and  so  on  until  stopped.     The  first  foot  of  each  of  ten 

1  'Time  in  English  Verse  Rhythm,'  Archives  of  Psychol.,  No.  10,  1908. 


341  WARNER  iJROPfN 

verses  was  measured  for  the  record.  The  force  is  the  height 
of  the  consonant,  and  the  duration  Is  the  time  from  the  begin- 
ning of  one  consonant  to  the  beginning  of  the  next.  Here  all 
the  conditions,  rhythmic  form,  motor  performance,  and  experi- 
mental conditions  for  making  the  record,  were  more  com- 
plicated than  in  the  case  of  taps.  The  difficulty  of  securing 
an  adequate  record  of  the  force  of  the  vocal  utterance  is  a 
particularly  serious  source  of  error,^  and  yet  when  we  re- 
member that  the  syllables  to  be  measured  are  all  made  up 
of  the  same  letters  or  sounds  the  data  may  be  considered 
sufficiently  reliable  for  our  purposes.  As  compared  with  the 
iambic  taps  there  is  a  very  large  Increase  In  variability  in  all 
directions,  and  while  the  larger  variation  In  force  may  be 
attributable  to  instrumental  difficulties,  the  loss  of  control 
in  time  is  beyond  question.  This  greater  variability  indicates 
that  the  greater  elaborateness  of  the  rhythm  or  the  change 
in  the  motor  mechanism,  or  the  experimental  embarrassments 
(which  were  not  grave)  singly,  or  together.  Interfered  with  the 
rhythm  in  respect  both  to  internal  structure  and  to  the  rela- 
tion of  the  units  to  one  another. 

Yet  apart  from  greater  Irregularity,  the  spoken  iambs  do 
not  differ  materially  from  those  that  were  tapped,  when  we 
consider  that  the  blame  for  the  relatively  greater  variability 
in  force  can  properly  be  laid  to  instrumental  difficulties.  In 
Table  II.  the  difference  between  time  and  force  was  more 
noticeable  in  the  ratio  column  than  in  any  other,  but  in  the 
present  case  the  ratios  differ  In  force  only  twice  as  much  as  in 
duration,  while  in  the  other  columns  the  force  varies  nearly 
three  times  as  much  as  the  duration.  This  is  not  to  be  taken 
as  Improvement  in  the  relative  regularity  of  structure  as 
regards  force,  but  again  as  a  peculiarity  of  the  recording 
device.  This  device  might  well  record  the  relative  emphasis, 
i.  <?.,  the  ratio  of  force,  within  the  foot,  while  it  would  not 
report  correctly  the  emphasis  in  different  feet,  or  over  any 
considerable  length  of  time. 

^See  'Time  in  Eng.  Verse  Rhythm,'  p.  22;  and  compare  Bourdon  in  Uannee 
psychologique,  IV.,  1898,  p.  370. 


TEMPORAL  AND  ACCENTUAL  RHYTHM 


34* 


IV 

In  the  fourth  part  of  the  experiment  the  subjects  were 
instructed  to  recite  into  the  recording  apparatus  in  a  natural 
but  forceful  manner  the  nursery  verses: 

Pease  porridge  hot, 
Pease  porridge  cold, 
Pease  porridge  in  the  pot  nine  days  old. 

Table  IV 

Pease  Porridge 

Showing  for  each  Subject  the  Mean  Variation  in  per  cent,  from  an  average  of  lo 
measurements  of  the  words  Pease  porridge  cold;  with  regard  to  Force  and  Duration. 
The  Variation  is  shown  for  each  word  separately,  for  the  Sum  of  the  three  words,  and 
for  the  Ratio  found  by  dividing  the  first  word  into  the  second. 


Pease 

Porridge 

Cold 

Sum 

Ratio 

Subject 

F 

D 

F 

D 

F 

D 

F 

D 

F 

D 

I 

15.28 

6.06 

10.86 

4.02 

14.29 

7-74 

9-75 

3-87 

14.68 

3.08 

2 

23.20 

11-55 

29.60 

7.II 

22.40 

6.01 

21.20 

5-71 

32.80 

14.05 

3 
4 
5 

12.40 

1 

8.87 
1 

13.00 

1 

8.28 
1 

10.17 

1 

6.80 

1 

8.07 
1 

3-85 
1 

22.05 
1 

14.51 

1 

1 

10.90 

1 

8.30 

1 

6.37 

1 

6.74 

1 

12.77 

6 

25-15 

9-77 

37-10 

4.II 

31-85 

7.76 

22.75 

5-54 

46.70 

8.01 

7 

26.60 

7.46 

15.80 

3.66 

15.80 

3-45 

16.30 

3.16 

22.80 

7-25 

8 

17.15 

13-50 

17.90 

7.26 

18.00 

5-54 

14-53 

4.87 

15.20 

17.70 

9 

16.00 

6.00 

16.60 

3.84 

31.70 

8.00 

17.20 

3-84 

15.40 

4-03 

10 

17.88 

6.50 

16.67 

6.24 

40.20 

8.04 

16.93 

3-56 

25.60 

9.85 

II 

20.20 

8.98 

22.20 

II. 18 

25.80 

3-96 

16.60 

3-36 

23.00 

19.30 

12 

11.90 

4.72 

10.70 

1.98 

32.40 

4.04 

7.71 

1-65 

16.65 

4.66 

13 

25.70 

7-05 

28.00 

5. 61 

32.40 

8.92 

15.40 

4-72 

43.00 

10.60 

H 

9-58 

6.02 

13.40 

6.87 

31.20 

12.40 

II. 15 

6.91 

19-25 

9.64 

IS 

24.80 

6.19 

17.60 

3-44 

25.70 

6.81 

13.00 

4-40 

38.60 

6.78 

Av. 

18.91 

8.11 

19.19 

5.86 

25-54 

6.84 

14.66 

4.44 

25-82 

10.16 

This  was  repeated  a  number  of  times.     The  record,  given 
in  Fig.  4  and  Table  IV.,  shows  the  variation  in  force  (height 


\rv^VN/V 


Fig.  4. 

of  the  initial  consonants  p,  p  and  c)   in  the  phrase  'Pease 
porridge  cold,'  and  in  time  from  the  beginning  of  pease  to  the 

^  No  legible  record. 


343  WARNER  BROWN 

beginning  of  porridge,  from  the  beginning  of  porridge  to  the 
beginning  of  cold,  and  in  the  duration  of  the  word  cold  to 
the  end  of  the  final  consonant.  It  also  shows  the  variations 
in  time  and  force  for  the  whole  phrase  of  three  words  and  in 
the  ratios  for  the  first  and  second  words  of  the  phrase.  The 
variations  are  based  on  the  average  of  ten  records  except  that 
in  three  cases  there  were  only  eight  available  records.  As 
elsewhere  the  variations  are  expressed  in  per  cent,  of  the 
quantities  involved. 

With  regard  to  either  the  time  or  force,  the  variations  in 
this  series  are  about  as  large  for  the  separate  parts  of  the 
foot  as  in  the  iambic  syllable  (ta  ta)  series.  The  variation 
in  force  exceeds  the  variation  in  time  in  about  the  same 
proportion  as  in  that  series.  But  the  variations  for  the  foot 
as  a  whole  fall  below  those  for  the  iambic  syllables.  In  dura- 
tion these  feet  are  about  as  regular  as  the  regular  taps  of  the 
first  series.  The  ratios  present  a  different  aspect,  for  while 
in  duration  they  are  slightly  more  regular  than  the  iambic 
syllables,  they  are  less  regular  in  force.  In  comparison  with 
the  series  of  iambic  syllables  the  'Pease  porridge'  series  is 
more  regular  in  recurrence  in  regard  to  both  the  time  and 
force  of  the  total  foot.  The  'Pease  porridge'  series  has  also  a 
more  regular  internal  structure  (ratio)  in  regard  to  time  but 
not  in  regard  to  force.  Loss  of  control  over  the  relative  force 
of  the  movements  is  very  evident  in  even  a  superficial  inspec- 
tion of  the  'Pease  porridge'  records.  The  relative  force  of 
the  two  p's  often  undergoes  a  complete  reversal  from  verse  to 
verse.  The  rhythm  of  this  verse  is  of  course  irregular  or  even 
amorphic  but  it  is  of  a  very  distinctly  temporal  type,  giving, 
all  the  disturbing  factors  being  considered,  very  great  regu- 
larity in  the  matter  of  recurrence,  together  with  a  relatively 
high  degree  of  regularity  in  internal  structure  so  far  as  the 
time  relations  are  concerned. 

With  these  concrete  examples  from  which  to  start  we 
are  now  in  a  position  to  discuss  with  more  understanding 
the  temporal  and  accentual  features  in  any  rhythm.  The  first 
point   to  be  observed   is   that   all   recurrence   is   a   temporal 


TEMPORAL  AND  ACCENTUAL  RHYTHM  344 

matter.  A  rhythm  is  temporal  in  so  far  as  there  is  any  regular 
return  of  similar  features.  But  at  the  same  time  such  a 
rhythm  will  also  be  accentual  since  there  must  always  be 
points  of  emphasis  whose  return  can  be  marked.  At  this  stage 
of  the  discussion  the  question  to  be  answered  is:  Which  is 
fundamental  to  the  rhythm;  the  uniform  time  of  recurrence, 
or  the  uniform  character  of  the  thing  that  recurs.^  Assuming 
a  reliable  method  of  measuring  both  the  thing  and  its  rate  of 
recurrence  I  propose  the  variability  as  a  test  in  this  question. 
If  the  movements  or  sounds  vary  in  intensity  more  than 
in  duration  or  more  than  the  interval  separating  them,  I 
submit  that  the  rhythm  is  primarily  temporal.  No  very 
extended  argument  seems  to  be  required  in  support  of  this 
view,  for  regularity  is  essential  to  rhythm,  and  if  the  regularity 
is  predominantly  in  the  time  relations  the  rhythm  may  be 
presumed  to  have  its  seat  there  also.  Accent  may  be  a 
necessary  feature  but  it  is  not  the  distinctive  feature  in  the 
rhythms  examined  for  this  study. 

But  we  can  not  stop  the  discussion  on  the  level  of  mere 
recurrence;  that  would  be  to  stop  with  the  whole  feet,  ignoring 
their  parts.  We  can  not  consider  the  mere  intensity  and 
duration  of  the  item  which  recurs;  we  must  also  consider  its 
individual  make-up  or  structural  character.  This  puts  us  on 
the  second  level,  that  of  the  structure  of  the  elements  com- 
posing the  rhythm.  Here  we  find  again  intensities  and  dura- 
tions, or  to  speak  more  accurately,  relations  of  intensity  and 
duration.  May  it  not  be  that  we  shall  find  in  one  or  the  other 
of  these  relations  something  that  will  present  greater  regular- 
ity than  the  mere  recurrence  of  the  elements?  If  so  we  may 
look  here  for  the  essence  of  the  rhythm. 

On  the  surface  of  the  returns  the  ratios  which  represent 
these  relations  appear  to  be  more  variable  than  the  periods 
of  recurrence.  But  as  the  writer  has  stated  before,^  this 
view  although  probably  correct  can  not  be  taken  as  final, 
because  the  ratios  are  apparently  incommensurable  with  the 
actual  durations.  But  we  can  face  this  difficulty  fairly,  and 
still  say  that  on  this  second  level  of  structural  form,  consider- 

1  'Time  in  English  Verse  Rhythm,'  p.  67. 


345 


WARNER  BROWN 


ing  the  ratios  independently,  it  is  in  the  temporal  structure 
and  not  in  the  accentual  structure  that  we  find  the  greater 
regularity.  If  the  fundamental  regularity  does  reside  in  the 
arrangement  of  the  parts  within  the  units  rather  than  in  the 
recurrence  of  these  units,  it  is  still  to  be  sought  in  the  arrange- 
ment of  the  parts  in  time.  In  any  event  the  predominant 
regularity  on  either  level  is  a  temporal  regularity. 

V 

A  somewhat  different  method  of  attack  leads  to  the  same 
conclusion.  If,  in  Table  V.,  we  consider  the  actual  ratios 
which  represent  the  structure  of  the  elements,  we  find  that 
the  ratios  for  force  of  movement  are  different  from  the  ratios 


Table  V 

Ratios 
Showing  for  each  Subject  the  average  absolute  amount  of  the  Ratio  found  by 
dividing  the  first  tap  or  syllable  into  the  second;  with  regard  to  Force  and  Duration. 


Iambic  Taps 

Ta  la 

Pease  porridge 

Subject. 

Cf.  Table  II 

Cf.  Table  III 

Cf.  Table  IV 

F 

D 

F 

D 

F 

D 

I 

1.22 

1.78 

1.68 

2.18 

1.09 

1. 10 

2 

1.29 

2-45 

1.23 

1.96 

.86 

1. 14 

3 

1.38 

1.71 

1.89 

2.56 

1. 14 

1^33 

4 

I-S7 

2.52 

2.46 

2.56 

5 

1.28 

1-73 

2.24 

2.93 

1. 14 

6 

1.87 

•95 

I-5S 

I.71 

1.02 

1. 14 

7 

1.87 

1.61 

1.92 

2.64 

•98 

1.09 

8 

1.58 

1. 19 

•94 

I.91 

.98 

1. 12 

9 

1.09 

1.79 

2.44 

3.06 

•99 

1.02 

ID 

1.24 

1.07 

1^53 

2.47 

•55 

•94 

II 

1.62 

2.94 

1.05 

2.13 

•93 

1. 16 

12 

1.27 

2.10 

1. 14 

2.00 

.72 

1.05 

13 

1.64 

1.82 

2.82 

2.84 

1. 16 

1.08 

14 

1. 17 

1.96 

1.77 

.67 

I-I3 

IS 

1.52 

2.47 

2. II 

3^3i 

.86 

1.49 

Average. 

1.44 

1.87 

1.78 

2.43 

.92 

1. 14 

for  duration  of  movement.  In  both  of  the  iambic  series  the 
time-ratios  are  larger  than  the  force-ratios.  That  is  to  say, 
the  typical  iambic  structure  with  the  second  part  outweighing 
the  first  part  is  more  adequately  or  fully  carried  out  in  time 
than  in  stress.  If  the  essence  of  the  rhythm  is  on  the  second 
level,  in  the  arrangement  of  the  parts  within  the  rhythmic 


TEMPORAL  AND  ACCENTUAL  RHYTHM  34^ 

unit,  then  again  the  arrangement  in  time  satisfies  the  require- 
ments more  fully. 

No  inferences  can  be  drawn  from  the  absolute  ratios  of 
the  'Pease  porridge'  records  because  there  is  no  evidence  that 
this  was  meant  by  the  speakers  to  be  an  iambic  ryhthm.  It 
has  some  of  the  ear-marks  of  a  trochaic  rhythm^  and  in  that  case 
we  do  not  know  whether  a  larger  or  smaller  ratio  stands  for 
the  typical  rhythm.  In  fact  the  absolute  ratio  fails  when 
applied  to  verse  rhythms  because  of  the  fact  here  illustrated 
that  the  time-ratio  is  determined  in  such  cases  by  the  neces- 
sary time  of  uttering  the  words.  The  second  word  in  this  verse 
appears  to  be  the  second  element  in  a  trochaic  foot;  it  sounds 
so  to  the  ear  and  its  initial  consonant  shows  in  the  record 
less  stress,  on  the  average,  than  the  initial  consonant  of  the 
first  word;  and  yet  it  takes  longer  to  say  the  longer  and  more 
complex  second  word.  In  verse  there  are  no  typical  time- 
ratios  and  the  force-ratios  are  not  easily  measured.  With  this 
exception  the  evidence  from  the  absolute  ratio  furnishes  a 
valuable  check  upon  the  evidence  from  the  relative  varia- 
bilities. 

These  results  are  presented  with  the  hope  of  arousing 
interest  In  what  appears  to  me  to  be  a  promising  method  for 
the  analysis  of  some  of  the  fundamental  questions  regarding 
the  basis  of  rhythmic  actions  and  impressions.  The  results 
themselves,  so  far  as  they  go.  Indicate  as  I  think,  that  the 
time  aspects  are  fundamental  and  that  the  accentual  features 
while  necessary  are  not  at  the  root  of  the  phenomena. 

1  Op.  cit.,  p.  55. 


STUDIES   FROM  THE   PSYCHOLOGICAL  LABOR- 
ATORY OF  THE   UNIVERSITY 
OF   CALIFORNIA 

XVII.    Some  Preferences  by  Boys  and  Girls  as  Shown 
IN  their  Choice  of  Words 


BY  M.  I.  STOCKTON 


Reprinted  from  the  Psychoi,ogicai.  Review,  September,  1911, 
Vol.  XVIII,  No.  5. 


[Reprinted  from  The  Psychological  Review,  Vol.  XVIII.,  No.  s,  Sept.,  ign-l 


XVII.    Some  Preferences  by  Boys  and  Girls  as  Shown 
IN  THEIR  Choice  of  Words 

BY  M.  I.  STOCKTON 

The  broader  purpose  of  the  experiments  reported  in  this 
paper  was  to  obtain  light  upon  possible  differences  in  the 
affective  life  of  children  at  different  ages,  and  especially  upon 
any  differences  between  boys  and  girls.  The  present  experi- 
ments were  limited,  however,  to  a  study  of  the  difference 
between  boys  and  girls  as  shown  in  their  choice  between  time 
and  space  words;  between  words  expressing  activity  and 
those  expressing  passivity;  between  words  relating  to  dress 
and  those  relating  to  food;  between  verbs  and  adjectives. 

These  experiments  were  suggested  by  the  conclusions 
stated  in  Mrs.  Manchester's  paper  on  'Unreflective  Ideas  of 
Men  and  Women. '^  The  question  in  her  study  was  whether 
there  is  any  difference  between  college  men  and  women  in 
their  unreflective  ideas.  From  the  results  of  her  experiment 
she  drew  the  following  general  conclusions: 

1.  The  surface  ideas  of  men  and  women  pertain  to  ob- 
jects which  are  familiar  and  interesting. 

2.  The  dynamic  aspect  of  objects  is  more  attractive  to 
men,  while  the  static  or  completed  aspect  appeals  more  to 
women. 

3.  Time  as  a  factor  enters  more  largely  into  the  surface 
ideas  of  men;  space  is  more  often  a  prominent  feature  of  the 
surface  ideas  of  women. 

4.  Men  make  a  greater  use  of  abstract  terms,  while 
women  show  a  preference  for  concrete  and  descriptive 
words. 

The  present  experiments  were  carried  out  in  all  the 
grades,  above  the  low  second,  of  the  Bay  Grammar  School, 
Oakland,  Cal.  The  accompanying  table  (Table  A)  gives  the 
age,  number  and  distribution  of  the  pupils  participating. 

1  Psychological  Review,  Vol.  12  (1905),  p.  50. 

347 


34« 


M.  I.  STOCKTON 


Method.— It  was  thought  that  if  a  pair  of  words  of  equal 
difficulty  and  familiarity  were  offered,  one  of  which  was  to  be 
selected,  although  several  motives  might  affect  the  choice, 
yet  perhaps  there  might,  after  elimination  and  check,  be  dis- 
covered some  clue  to  the  attractiveness  of  the  ideas  themselves. 
Four  lists  of  twenty  pairs  of  words  were  selected.  In  the  first 
list,  each  pair  was  composed  of  a  time  word  and  a  space  word; 
in  the  second  list,  of  a  word  denoting  activity  and  one  denoting 
passivity;  in  the  third  list,  of  one  referring  to  dress  and  one 
referring  to  food;  in  the  fourth  list,  of  a  verb  and  an  adjective. 

Table  A 


Average  Number  of  Pupils  Participating  in 

Average  Age 

Grade 

the  Four  Sets  of  Experiments 

Boys 

Girls 

Boys 

Girls 

B2 

21 

19 

9-3 

8.6 

A3 

20 

17 

lO.I 

9-3 

B3 

14 

17 

10.9 

9-3 

A4 

21 

17 

10.9 

II 

B4 

9 

8 

12.4 

I1.7 

As 

6 

17 

II-3 

12. 1 

Bs 

II 

IS 

13-9 

12. 1 

A6 

18 

12 

13-3 

12.9 

B6 

4 

8 

13-6 

14 

A? 

14 

13 

13-6 

12.9 

By 

6 

9 

H-S 

14 

A8 

4 

6 

14.6 

14-3 

B8 

2 

4 

15.6 

iS-3 

Each  pair  of  words  was  written,  one  directly  under  the 
other,  on  a  large  card  which  every  pupil  could  see  distinctly 
when  the  teacher  showed  it  to  the  class.  The  cards  were 
numbered  so  that  the  words  could  be  presented  in  order. 
The  words  were  so  written  that  if  a  time  word  was  first  on 
one  card,  a  space  word  was  first  on  the  next  following;  a  time 
word  on  the  third  and  so  on.  In  this  way,  any  preference 
due  to  the  position  of  the  word  on  the  card  would  be  offset. 
Such  an  order  was  carefully  followed  in  each  of  the  four  lists, 
as  will  be  seen  by  glancing  at  the  words  on  pages  349  and  350. 

Before  the  cards  were  presented,  paper  was  distributed  to 
the  pupils.  They  were  told  to  write  only  one  of  the  two 
words  that  appeared  on  each  card.  No  further  information 
concerning  the  work  was  given.     With  the  exception  of  the 


PREFERENCES  IN  BOYS  AND  GIRLS 


349 


third  set  of  papers  from  the  eighth  grade,  the  words  were 
written  by  the  pupils  of  the  twelve  different  classes  at  the 
the  same  hour  on  each  of  the  four  days. 

The  lists  containing  time  and  space  words  and  words 
denoting  activity  and  passivity  were  given  on  the  first  day. 
These  have  been  designated  Set  I.  Set  II.  was  given  five  weeks 
later  and  contained  the  list  of  words  pertaining  to  dress  and 
food  and  the  list  of  verbs  and  adjectives.  Set  III.  was  com- 
posed of  the  words  of  Set  I,  but  the  order  of  the  words  of 
each  pair  was  reversed.  In  this  way,  a  time  word  that  had 
been  first  of  a  pair  in  Set  I.,  was  second  of  the  same  pair  in 
Set  III.  By  this  double  check — that  is  by  alternating  within 
the  set  itself  the  class  of  word  that  appeared  first  on  each 
card  of  the  twenty,  and  by  reversing  in  Set  III.  the  position 
of  each  word  in  its  pair  as  it  appeared  in  Set  I.  —  any  influence 
which  might  be  due  to  preference  for  a  word  merely  because 
it  was  first  or  second  in  its  pair  would  probably  in  the  long  run 


Time 

mile 
year 

List  i 
and  Space  Words 

little 
month 

IvIST  2 

Words  Denoting  Activity  and  Passivity 
run                                       romp 
sit                                            hush 

always 
under 

soon 
tall 

rest 
busy 

calm 
move 

big 

now 

down 
daily 

swim 
still 

lively 
softly 

later 
small 

tomorrow 
thickness 

sleep 
work 

silent 

hurry 

where 
when 

width 
quick 

talking 
listen 

chatter 
slumber 

hour 
high 

seldom 
narrow 

quiet 
throw 

patient 
speaking 

inch 
slow 

above 
fast 

dig 
wait 

climb 
float 

early 
large 

yesterday 
outside 

idle        " 
jump 

grow 
push 

below 
today 

broad 
until 

play 
ride 

day 
night 

then 
there 

time 
space 

evening 
morning 

standing 
chasing 

350 


M.  I.  STOCKTON 


List 

3 

List  4 

Words  Relating  to  Dress  and  Food 

Verbs  and  Adjectives 

dress 

collar 

build 

sing 

grapes 

cheese 

little 

poor 

nut 

banana 

fresh 

old 

cap 

ribbon 

threw 

buy- 

hat 

velvet 

give 

sailed 

pie 

apple 

hot 

happy 

berries 

supper 

large 

green 

gloves 

cloak 

grow 

lived 

coat 

silk 

tell 

sold 

calie 

food 

good 

glad 

bread 

beef 

rich 

long 

sivirt 

lace 

pick 

make 

vest 

tailor 

looked 

run 

meat 

turkey 

short 

red 

fruit 

pudding 

*  sweet 

kind 

shoes 

necktie 

think 

jump 

stockings 

button 

follow 

slept 

potatoes 

carrot 

sunny- 

small 

butter 

dinner 

fine 

merry 

woolen 

shawl 

eat 

break 

be  compensated.  The  third  set  was  presented  two  weeks  after 
the  second  set.  Set  IV.  contained  the  words  of  Set  II.  in 
reverse  order  and  was  given  three  weeks  later  than  Set  III. 

The  pupils  of  the  A  second  grade  because  of  insufficient 
power  of  writing  were  unsuited  to  the  experiment;  so  the  B 
second  grade  is  the  youngest  class  employed,  and  is  referred 
to  simply  as  the  second  grade.  There  were  so  few  pupils  in 
the  eighth  grade  that  the  results  of  the  two  divisions  together 
have  been  given  as  the  eighth  grade.  The  work  of  the  A 
fourth  grade  was  interrupted  on  two  mornings,  so  there  is 
only  one  set  of  papers  for  the  list  of  verbs  and  adjectives  and 
for  the  list  containing  words  denoting  activity  and  passivity. 

Many  difficulties  beset  one  in  preparing  the  lists  of  words. 
There  were  serious  limitations  placed  upon  selection  by  the 
difference  in  ability  of  the  various  classes.  It  was  necessary 
that  the  two  words  of  a  pair,  fairly  intelligible  and  within 
the  vocabulary  of  the  pupils,  should  be  of   the  same  length 


PREFERENCES  IN  BOYS  AND  GIRLS  35  ^ 

and  of  the  same  degree  of  difficulty  In  writing.  Although 
much  time  was  spent  In  preparing  the  lists,  It  Is  Impossible 
to  feel  that  they  are  entirely  satisfactory  or  beyond  criti- 
cism. 

The  results  are  arranged  In  Tables  I.  to  IV.  which  show 
the  percentage  of  each  class  of  words  selected  by  the  boys 
and  girls  respectively  In  the  different  grades  and  also  the  per- 
centage of  first  and  second  words  selected  In  the  same  lists. 
The  percentages  are  given  for  each  set  of  papers  obtained  from 
each  of  the  four  lists  of  words  and  also  the  average  percentage 
of  the  two  sets. 

In  Table  V.,  the  total  number  of  each  class  of  words 
selected  by  the  twelve  grades  Is  given  with  the  corresponding 
number  of  first  and  second  words  chosen.  The  percentage 
selected  Is  also  shown.  The  more  significant  figures  are  those 
given  as  percentages  of  the  different  classes  of  words  selected. 
The  total  number  of  words  is  of  less  value  since  the  proportion 
of  boys  and  of  girls  varies  in  the  different  grades. 

Plates  A  to  D  inclusive  give  in  different  form  the  same 
results  as  are  given  In  Tables  I.  to  IV.  The  ordlnates  repre- 
sent the  percentages  of  preference;  the  abscissae  represent  In 
order  the  different  school  grades.  The  average  value  of  each 
curve  for  all  twelve  grades  is  also  shown  In  each  table  by  the 
horizontal  lines;  e.  g.,  the  horizontal  line  composed  of  a  dot 
and  a  dash  in  Plate  A  represents  the  average  selection  of 
time  words  for  the  twelve  grades  for  the  boys, — having  a 
value  of  53.9  per  cent.  Plate  E  shows  the  average  percentage 
of  the  different  classes  of  words  and  of  first  and  second  words 
for  the  twelve  grades  combined. 

Let  us  consider,  first,  what  conclusions  one  Is  warranted 
in  drawing  with  regard  to  the  more  limited  problem  of  this  ex- 
periment; and  later  the  relation  of  these  results  to  the  larger 
field  will  be  of  Interest. 

The  averages  of  the  two  sets  In  Tables  I.-IV.  are  the  signifi- 
cant figures;  for  any  apparent  preference  due  merely  to  the 
order  of  the  words  is  probably  eliminated  by  the  alterna- 
tion and  reversal  of  words  explained  on  page  348.  From 
Table  I.  and  its  graphic  presentation  In  Plates  A  and  E,  one 


352 


M.  I.  STOCKTON 


Table  I 

Percentage  of  Words  Chosen 


Character  of  the  Word 


Second  Grade. 

First  set 

Third  set.  .  .  . , 

Average 

A  Third  Grade. 

First  set 

Third  set.  .  .  . 

Average 

B  Third  Grade. 

First  set.  . .  . . 

Third  set.  .  .  . 

Average 

A  Fourth  Grade. 

First  set 

Third  set.  .  .  . 

Average 

B  Fourth  Grade. 

First  set 

Third  set.  .  .  . 

Average 

A  Fifth  Grade. 

First  set 

Third  set.  .  .  . 

Average 

B  Fifth  Grade. 

First  set 

Third  set.  .  .  . 

Average 

A  Si.xth  Grade. 

First  set  .... 

Third  set.  .  .  . 

Average 

3  Sixth  Grade. 

First  set 

Third  set.  .  .  . 

Average 

A  Seventh  Grade. 

First  set 

Third  set.  .  .  . 

Average 

B  Seventh  Grade. 

First  set 

Third  set.  .  .  . 

Average 

Eighth  Grade. 

First  set 

Third  set.  .  .  . 

Average 


Boys 


Time     Space      First     Second 


54-2 
49.6 

51.8 

53-7 
57-4 
SS-5 

SS4 
Si.o 

53-2 

56.2 
54-6 
SS-4 

50.0 
50.2 
SO.  I 

54-2 
50.7 
52.5 

49.0 
56.0 
52.5 

54-7 
51-4 

S3-0 


SS-o 
Si-9 

S6.6 
58.8 
57-7 

58.8 
47-9 
53-3 

60.8 

Si-3 
56.0 


45.8 

50.4 
48.2 

46.3 
42.6 

44-5 

44-6 
49.0 
46.8 

43-8 
45-4 
44.6 

50.0 
49.8 
49.9 

45-8 
49-3 
47-5 

SI.O 
44.0 
47-S 

45-3 
48.6 
47.3 

SI.2 
45 -o 

48.1 

43-4 
41.2 

42.3 

41.2 

52.1 
46.7 

39-2 
48.7 
44.0 


43-9 
42.9 

43-4 

56.3 
60.4 

58-4 

37-6 
69.2 
53-4 

507 
58.9 
54-8 

55-5 
72-3 
63-9 

34-2 
62.1 

48.2 

40.0 
61.4 
507 

52.2 
63-9 
58.1 

537 
55-0 
54-4 

44.6 
64-3 
54-5 

43-8 
68.9 

56.4 

53-3 
68.8 
61. 1 


56.1 
57-1 
56.6 

437 
39.6 
41.6 

62.4 
30.8 
46.6 

49-3 
41. 1 

45.2 

44-5 
27.7 
36.1 

65.8 

37-9 
SI.8 

60.0 
38.6 
49-3 

47.8 
36.1 
41.9 

46-3 
45 -o 
45.6 

55-4 
357 
45-5 

56.2 
3I-I 
43-6 

46.7 
31.2 

38.9 


Girls 


Time  '  Space      First     Second 


48.6 
50.4 
49-5 

53-1 
53-3 
53-2 

52.5 
SI.O 

517 

53-0 
43-3 
48.1 

SI.9 

53-4 
52.6 

50.9 
52.8 
51-8 

557 
55-4 
55-5 


53-9 
51-3 

507 
50.0 

50-3 

537 
55-9 

54-8 

557 
69.  s 
62.6 

57-9 
49.1 

53-5 


514 
49.6 

50.5 

46.9 
46.7 
46.8 

47-5 
49.0 

48.3 

47.0 
567 
51-9 

48.1 
46.6 
47.4 

49.1 

47.2 


44-3 
44.6 

44-5 

SI.2 
46.1 

487 

49-3 
50.0 

497 

46-3 
44.1 

45-2 

44-3 
30.5 
37-4 

42.1 
50.9 
46.5 


50.5 
62.1 

56.3 

62.7 
64.2 
634 

37-2 
69.2 
53-2 

SI.O 
53-9 

524 

33-1 
46.6 

39-8 

42.9 
47.2 
SO.  I 

44-3 
59-3 
SI.8 

51-2 

707 
60.9 

67.8 

74-3 
71. 1 

48.9 
67.2 
58.1 

52.2 
587 
55-5 

36.7 
80.0 

58.3 


49-5 
37-9 
437 

37-3 
35-8 
36.6 

62.8 
30.8 
46.8 

49.0 
46.1 
47.6 

66.9 

534 
60.2 

57-1 
42.8 

49-9 

557 
40.7 
48.2 


29-3 
39-1 

32.2 

257 
28.9 

SI. I 
32.8 
41.9 

47.8 
41.2 
44-5 

63-3 
20.0 
417 


PREFERENCES  IN  BOYS  AND  GIRLS 


353 


I 
,      /I 


*? 


A 


A 


A^ 


7-V- 


/ 

< 

/ 

A' 

li  \ 


^oys:  -r/Afe 


G/fiUSi  T/**» 


V 

K 
I  \ 

I  \ 


A  h ! 


yV 


A 


A  \ 


IX. 


,_^/J% l_^ 


-\"\ — ; 


\   : 
i  t 

>/ 
I  «; 
*.  » 
•..1 
'••'I 

\ 

I 

I 

I 

.1 

t 

I 

I 


<s/yfi^ .'  ^s»<tClS 


BOKS:  g»>IC4t 


£      AS    £3  /4^    .<94»    /*r     iS5-  ^<5      ^<5    >«r    XT     3 

Plate  A.  Choice  between  time-words  and  space-words,  selected  by  boys  and 
girls  respectively.  The  ordinates  indicate  in  per  cent,  the  amount  of  preference 
shown  for  each  of  the  two  groups  of  words;  the  abscissae,  the  school-grades.  (From 
Table  I.) 


354 


M.  I.  STOCKTON 


Table  II 

Percentage  of  Words  Chosen 


Character  of  the  Word 


Second  Grade. 

First  set 

Third  set.  .  .  . 

Average 

A  Third  Grade. 

First  set 

Third  set.  .  .  . 

Average 

B  Third  Grade. 

First  set 

Third  set.  .  .  . 

Average 

A  Fourth  Grade. 

First  set 

B  Fourth  Grade. 

First  set 

Third  set.  .  .  . 

Average 

A  Fifth  Grade. 

First  set 

Third  set.  .  .  . 

Average 

B  Fifth  Grade. 

First  set 

Third  set.  .  .  . 

Average 

A  Sixth  Grade. 

First  set 

Third  set.  .  .  . 

Average 

B  Sixth  Grade. 

First  set 

Third  set.  .  .  . 

Average 

A  Seventh  Grade 

First  set 

Third  set.  .  .  . 

Average 

B  Seventh  Grade. 

First  set 

Third  set.  .  .  . 

Average 

Eighth  Grade. 

First  set 

Third  set.  .  .  . 

Average 


Boys 

Girls 

Ac- 
tivity 

Pass- 
ivity 

First 

Second 

Ac- 
tivity 

Pass- 
ivity 

First 

Second 

49- S 
46.8 
48.2 

50.5 
53-2 
SI.8 

45-4 
41.6 

43-5 

54-6 

58.4 

56.5 

53-5 
53-2 
53-4 

46-5 
46.8 
46.6 

48-5 
54-8 
SI.6 

Si-S 
45-2 
48-4 

51-6 
51.8 
Si-7 

48.4 
48.2 
48-3 

60.5 

51-5 
56.0 

39-5 
48.5 
44.0 

50.0 
50-5 

48.9 
50.0 

49-5 

57-1 
63-4 
60.3 

42-9 
36.6 

39-7 

54-5 
41.6 
48.0 

4S-S 
58.4 
52.0 

447 
63-9 
54-3 

55-3 
36.1 
457 

54-2 
49.1 
51-6 

45-8 
50.9 
48.4 

45-1 

58.3 
517 

54-9 
41.7 

48.3 

50.9 

49.1 

52.9 

47.1 

46.0 

54-0 

SI.O 

49.0 

48.3 
Si-3 
49.8 

517 
48.7 
50.2 

60.6 
67.4 
64.0 

39-4 
32.6 
36.0 

43-1 
36.1 

39-6 

56.9 
63-9 
60.4 

39-4 
57-9 
48.6 

60.6 
42.1 
51-4 

45-4 
53-9 
49.6 

54-6 
46.1 

S0.4 

36.2 
61.8 
49.0 

63.8 
38.2 
Si.o 

SO.  I 
48-S 
49-3 

49-9 
51-S 
50.7 

51.2 
51-5 
Si-4 

48.8 
48.5 
48.6 

49-S 
58.9 
54-2 

So-S 
41. 1 

45-8 

46.5 
50.3 
48.4 

53-5 
497 
51.6 

48.1 
49.2 
48.6 

Si-9 

50.8 

51-4 

47-5 
53-1 
50.3 

52.5 
46.9 

49-7 

54-5 
50.6 

S2-S 

45-S 
49-4 
47-S 

47-S 
70.1 
58.8 

52.5 
29.9 
41.2 

51-2 
48.8 
50.0 

48.8 

SI-2 
50.0 

53-5 
42.2 
47.8 

46-5 
57-8 

52.2 

56.2 
54-5 

SS-4 

43-8 

4S-S 
44.6 

71.2 

48.S 
59-8 

28.8 

51-5 
40.2 

47.1 
43-6 
45-4 

52-9 
56.4 
54-6 

72.8 
73-6 

73-2 

27.2 
26.4 
26.8 

517 

57.2 

54-5 

48.3 
42.8 

45-5 

52.3 
597 
56.0 

477 
40-3 
44.0 

50-4 
45-6 
48.0 

49-6 
54-4 
52-0 

56.1 
56-9 
56.5 

43-9 
43-1 
43-5 

47-5 
49.1 

48.3 

52.5 
50.9 
517 

52.5 
70.2 
61.4 

47-S 
29.8 
38.6 

44-3 
43-5 
43-9 

557 
56-S 
56-1 

52-8 
57-1 
54-9 

47.2 
42.9 
45-1 

52.1 
46.4 
49-3 

47-9 
53-6 
50.7 

49.6 

737 
61.6 

50.4 
26.3 
38-4 

48.3 

52.2 

50-3 

51-7 
47-8 
49-7 

39-2 
84.1 
61.6 

60.8 
15-9 

38.4 

PREFERENCES  IN  BOYS  AND  GIRLS 


355 


•ief 


7  t 
,t  '• 
I    \ 


N 
/  ^ 
/ 

/A 


G//fLS  :  fiASS/i^/Ty 


!    V 


\/ 


\\\A[_    1 

^^^kyr.i-"^^-  -K" ^W 


\  A 


-.1^ — «. 
\; 


i.w.uA/_:.r4_..^-i k 


Si*    I  • 

V 


'  ;  V      V/ \  ;    \  \  /   »'   / 


.-*'9/. 
.■S<S? 


\  I 

\  I 


A 


V' 


\ 


I 
\  I 


\  ! 


£    /i3    £3    A-9  £-9^    yiS     Sff   y^(5     JB<S    A7    S7    3 
Plate  B.     Choice  between  words  denoting  activity  and  passivity  by  boys  and 
girls  respectively.     The  ordinates  indicate  in  per  cent,  the  preference  shown  for  each 
of  the  two  groups  of  words,  the  abscissae,  the  school-grades.     (From  Table  II.) 

may  conclude  that  a  noticeable  predominance  of  time  interest 
is  shown  by  both  boys  and  girls.  There  is  a  slightly  greater 
predominance  of  time  interest  among  the  boys  than  among 
the  girls.  In  these  same  sets  of  time  and  space  words,  there 
is  a  predominance  of  first  words  in  ten  grades  among  the 
boys  and  in  eleven  grades  among  the  girls. 


356 


M.  I.  STOCKTON 


Table  III 

Percentage  of  Words  Chosen 


Character  of  Word  Chosen 


Second  Grade. 

Second  set.  . 

Fourth  set.  . 

Average.  .  .  . 
A  Third  Grade. 

Second  set.  . 

Fourth  set.  . 

Average.  .  .  . 
B  Third  Grade. 

Second  set.  . 

Fourth  set.  . 

Average.  .  .  . 
A  Fourth  Grade. 

Second  set.  . 

Fourth  set.  . 

Average.  .  .  . 
B  Fourth  Grade. 

Second  set.  . 

Fourth  set.  . 

Average.  .  .  . 
A  Fifth  Grade. 

Second  set.  . 

Fourth  set.  . 

Average.  .  .  . 
B  Fifth  Grade. 

Second  set.  . 

Fourth  set.  . 

Average.  .  .  . 
A  Sixth  Grade. 

Second  set. . 

Fourth  set.  . 

Average.  .  .  . 
B  Sixth  Grade. 

Second  set.  . 

Fourth  set.  . 

Average.  .  .  . 
A  Seventh  Grade. 

Second  set.  . 

Fourth  set.  . 

Average.  .  .  . 
B  Seventh  Grade 

Second  set.  . 

Fourth  set.  . 

Average.  .  .  . 
Eighth  Grade. 

Second  set.  . 

Fourth  set.  . 

Average.  .  .  . 


Boys 


Girls 


Dress 

Food 

First 

Second 

Dress 

Food 

First 

Second 

50.7 
48.S 
49.6 

49-3 
51-5 
S0.4 

60.3 
39-6 
49.9 

397 
60.4 
SO.  I 

S0.8 

37-3 
44.1 

49.2 
62.7 
55-9 

56.1 
517 
53-9 

43-9 
48.3 
46.1 

49-9 
497 
49.8 

SO.  I 
SO-3 

50.2 

41-3 
72.6 

56.9 

587 
27.4 

43-1 

58.1 
50.8 

54-5 

41.9 
49.2 
45-5 

527 
72.1 
62.4 

47-3 
27.9 

37-6 

41. 1 

SS-4 
48.3 

58.9 
44.6 

S17 

53-3 
64.8 

59-1 

46.7 
35-2 
40.9 

41. 1 

44-5 
42.8 

58.9 
55-5 
57-2 

53-5 
57-4 

ss-s 

46.S 
42.6 
44-S 

40.0 
42.9 
4I-S 

60.0 
57-1 

58.5 

S9-0 
57-1 
S8.i 

41.0 

42.9 
41.9 

39-6 
43-1 
41.4 

60.4 

56.9 
58.6 

46.4 

57-3 
51.8 

53-6 
42.7 
48.2 

497 
45-5 
47.6 

S0.3 
54-5 
52.4 

61.3 
57-1 
S9-2 

387 
42.9 
40.8 

45-0 
47.6 

46.3 

55-0 
52.4 
537 

42.9 

59-5 
SI.2 

57-1 
40.S 
48.8 

42.2 
41.7 
41.9 

57.8 
58.3 
S8.i 

51-9 
44.8 
48.4 

48.1 
SS.2 
SI.6 

49.1 
49-4 
49-3 

50.9 
50.6 

507 

52.3 
57-9 
55-1 

477 
42.1 

44-9 

56.4 
31-5 
43-9 

43-6 
68.5 
56.1 

66.1 
53-2 
59-6 

33-9 
46.8 
40.4 

44.8 
44.1 
44-5 

SS.2 
55-9 
55-5 

51-3 
S8.1 

547 

487 
41.9 

45-3 

38.S 
28.9 

337 

61.5 
71. 1 

66.3 

63.6 
66.1 
64.8 

36.4 
33-9 
35-2 

SS-9 

52.9 
54-4 

44.1 
47.1 
45.6 

67.9 
67.1 
67.5 

32.1 
32-9 
32.5 

30.0 
20.0 
25.0 

70.0 
80.0 
7S-0 

57-5 
65.0 
61.3 

42.5 
35-0 
387 

44.1 
45 -o 
44-5 

55-9 
5S-0 
55-5 

77-4 
67.S 
72.S 

22.6 
32.5 
27-5 

37-6 
18.6 
28.1 

62.4 
81.4 
71.9 

56.2 
53-6 
S4-9 

43-8 
46.4 

45-1 

377 
24.1 

30-9 

62.3 

75-9 
69.1 

45-8 
55-5 
50.6 

54-2 
44-5 
49-4 

52.5 
34-2 
43-4 

47-5 
65.8 
56.6 

50.8 

42.S 
46.6 

49.2 
57-5 
53-4 

53-6 
40.6 
47.1 

46.4 
59-4 
52.9 

50.3 
57-3 
53-8 

497 
427 
46.2 

4S-8 
38.8 
42-3 

54-2 
61.2 
577 

57-5 
71.2 
64.4 

42.5 
28.8 

35-6 

47.1 
45-9 
46-5 

52-9 
54-1 
53-5 

53-8 
587 
56.3 

46.2 
413 
437 

PREFERENCES  IN  BOYS  AND  GIRLS 


357 


1   \ 

I      \ 


ad 


( 
I 


«3-<? 


*r  • 


/J 


/\ 


/ 


/ 


V 


v 


\ 

..Ji. 


/Vv 


fn 


[  . 

1 

ii 

,'!i 

i 

'  11, 

/ 

It 

f 

i 

\\    '/ 

/ 

•l^- 

/ 

r- 

Soys.'/^oo 


0//fLS.  fiJ90Z> 


'  y 


G//fi3:J3f9&S9y 


Boy^:ZiKGSS 


I// 

f 

I 
( 
f 
I 


<e     ^43   ,<a5   w-^  ^^  yfS  -3^  ^^  -^-^   A7  /57'    S 

Plate  C.  Choice  between  words  denoting  food  and  dress,  by  boys  and  girls 
respectively.  The  ordinates  indicate  in  per  cent,  the  amount  of  preference  shown  for 
each  of  the  two  groups  of  words;  the  abscissae,  the  school-grades.     (From  Table  III.) 


358 


M.  I.  STOCKTON 


Table  IV 

Percentage  of  Words  Chosen 


Character  of  Word  Chosen 


Second  Grade. 

Second  set.  .  , 

Fourth  set.  .  , 

Average .  .  .  . , 
A  Third  Grade. 

Second  set.  . 

Fourth  set.  . 

Average .  .  .  . , 
B  Third  Grade. 

Second  set.  .  , 

Fourth  set.  .  , 

Average 

A  Fourth  Grade. 

Fourth  set.  .  , 
B  Fourth  Grade. 

Second  set.  . 

Fourth  set.  . 

Average .... 
A  Fifth  Grade. 

Second  set.  . 

Fourth  set.  . . 

Average .... 
B  Fifth  Grade. 

Second  set.  . 

Fourth  set.  . 

Average .... 
A  Sixth  Grade. 

Second  set.  . 

Fourth  set.  . 

Average.  ... 
B  Sixth  Grade. 

Second  set.  . 

Fourth  set.  . 

Average.  .  .  . 
A  Seventh  Grade. 

Second  set.  . 

Fourth  set.  . 

Average.  .  .  . 
B  Seventh  Grade. 

Second  set  .  . 

Fourth  set.  . 

Average.  ... 
Eighth  Grade. 

Second  set.  .  , 

Fourth  set.  .  , 

Average .... 


Boys 

Verbs 

Adjec- 
tives 

First 

Second 

45-8 
45-3 
4S-S 

54.2 
547 
S4-S 

587 
40.8 

497 

41-3 
59-3 
S0.3 

43-1 
45.6 

44-4 

56.9 
54-4 
5S-6 

55-4 
69.7 
62.5 

44.6 
30.3 
37-5 

437 
46.2 
44.9 

56.3 
53-8 
55-1 

66.9 
69.6 
68.3 

33-1 
30.4 
317 

447 

55-3 

51.9 

48.1 

44.0 
43-8 
43-9 

56.0 
56.2 
56.1 

61.0 
67.2 
64.1 

39-0 
32.8 

35-9 

37-2 
47-3 
42.3 

62.8 
527 
577 

50.0 
48.4 
49.2 

50.0 
51.6 
50.8 

38.8 

427 
40.7 

61.2 
57-3 
59-3 

62.7 
50-4 
56.5 

37-3 
49.6 

43-5 

46.9 
42.9 
44-9 

53-1 
57-1 
55-1 

65.2 
69.6 
67.4 

34-8 

30.4 
32.6 

41.9 

40.  s 

41.2 

S8.i 

59-5 
58.8 

67.6 
50.6 
59-1 

32.4 
49-4 
40.9 

41.9 
39-8 
40.8 

58.1 
60.2 
59-2 

61. 1 

59-8 
60.5 

38.9 
40.2 

39-5 

4S-8 
49.2 

47-5 

54-2 
50.8 
52.5 

67-5 
44.2 

55-8 

32.5 
55-8 
44.2 

35-9 
43-1 

39-5 

64.1 

56.9 
60.5 

57-5 
70.9 
64.2 

42-5 
29.1 

35-8 

Girls 


Verbs     Adjec-     pi^st     Second 
tives 


46.8 

36.4 
41.6 

43-4 
46.6 

45 -o 

42.2 
42.1 
42.2 

43-3 

42.5 
38.5 
40.5 

41.2 
43-3 
42-3 

40.7 

36.5 
38.6 

43-3 
517 
47-5 

45-6 
41.9 

437 

40.7 
38.9 
39-8 

48.1 
41. 1 
44.6 

41.2 

43-9 
42.5 


53-2 
63.6 

58.4 

56.6 
53-4 
55-0 

57-8 
57-9 
57-8 

567 

57-5 
61.S 
59-5 

58.8 
567 
577 

59-3 
63-5 
61.4 

567 
48.3 
52.5 

54-4 
58.1 
56.3 

59-3 
61. 1 
60.2 

51-9 
58.9 

SS-4 

58.8 
56.1 

57-5 


59-5 
54-4 
56.9 

62.4 
80.1 
71-3 

56.9 
64.1 

60.5 

56.3 

49.1 
63.2 
56.2 

60.8 
62.4 
61.6 

577 
55-6 
56.6 

58-9 
57-5 
58.2 

79-4 
70.6 

75 -o 

45.6 

54-5 
50.1 

55-8 
58.9 
57-4 

54-3 
56.7 
55-5 


40-5 
45.6 

43-1 

37-6 
19.9 

28.7 

43-1 
35-9 
39-5 

437 

50.9 
36.8 
43-8 

39-2 
37-6 
38.4 

42.3 
44.4 

43-4 

41. 1 
42.5 
41.8 

20.6 
29.4 

25.0 

54-4 

45-5 
49-9 

44.2 
41. 1 
42.6 

457 
43-3 
44-5 


PREFERENCES  IN  BOYS  AND  GIRLS 


359 


..       A^-^.—--' 


/\ 


/I 


I  .soys:^u>s/£cr/k'£ 


A 


iV  / 


11 

U 


••A-''-"-~X 


1/ •, 


"/"*■"(*' 


"\ — 

\ 


/N 


.•.'.\.--K«' 


A 


u 


L 


V 


f 


.aoxs:  i^^eRO 


&     y\3     S3    X'5'    S0    >W     .S^   >»<5     ^tf   /\7     ST     3 


Plate  D.  Choice  between  verbs  and  adjectives  by  boys  and  girls  respectively. 
The  ordinates  indicate  in  per  cent,  the  amount  of  preference  shown  for  each  of  the  two 
groups  of  words;  the  abscissae,  the  school-grades.     (From  Table  IV.) 


Table  11.  and  Plates  B  and  E  show  a  slight  preference 
among  the  boys  for  words  denoting  activity  and  not  quite  so 
great  a  preference  among  the  girls  for  words  denoting  pas- 
sivity. The  preference  for  first  words  is  shown  in  nine  grades 
among  the  boys  and  in  ten  grades  among  the  girls. 

Table  III.  and  Plates  C  and  E  show  a  preference  for  words 


36o 


M.  I.  STOCKTON 


pertaining  to  food  among  both  boys  and  girls.  The  preference 
is  more  marked  among  the  boys  and  is  shown  for  all  the 
grades  (Plate  C);  whereas  it  is  shown  in  ten  of  the  grades 
among  the  girls.  The  greatest  difference  in  the  choice  of 
contrasting  words  is  shown  here  in  the  result  for  the  boys 
of  the  B6  and  Ay  grades.  There  is  a  predominance  here  of 
first  words  in  nine  grades  among  the  boys  and  in  all  grades 
among  the  girls. 

Table  V 

Showing  the  total  number  and  percentage  of  each  class  of  words  chosen  and  also 
the  total  number  and  percentage  of  first  and  second  words  chosen. 


Time 

Space 

First        Second 

Activ. 

Passiv. 

First 

Second 

Boys 

Girls 

3206 

53-9 
3458 

52.8 

2743 

46.1 
3084 

47.2 

3233 

54-3 
3562 

54-5 

2716 

457 
2980 

45-5 

2812 

5I-I 
3039 
49.1 

2688 

48.9 
3153 

50.9 

2976 

54-1 
3310 

53-5 

2524 

45-9 

2882 
46.5 

Dress 

Food 

First 

Second 

Verb 

Adj. 

First 

Second 

Boys 

Girls 

2467 

41.9 
2942 

45-4 

3409 

58.1 
3544 

54-6 

3336 

56.7 
3666 

56.6 

2540 

43-3 
2820 

43-4 

2408 

437 
2584 

42-5 

3100 

56.3 
3492 

57-5 

3267 

59-3 
3614 

S9-S 

2241 

40.7 
2462 

40-5 

Table  IV.  and  Plates  D  and  E  show  a  predominance  of 
adjectives  in  all  the  grades  among  both  boys  and  girls;  here 
the  preference  is  greater  among  the  girls.  There  is  a  pre- 
dominance of  first  words  among  the  girls  in  all  grades  and 
among  the  boys  in  ten  grades. 

Although  Mrs.  Manchester's  work  was  upon  men  and 
women,  nevertheless  a  comparison  of  these  results  with  hers 
is  interesting.  The  element  of  time  was  more  noticeable 
among  the  ideas  of  men  and  that  of  space  among  the  ideas 
of  women.  These  boys  and  girls  alike  show  a  preference  for 
time  ideas — the  preference  being  slightly  greater  among  the 
boys.  The  idea  of  activity  was  characteristic  of  the  men's 
lists  while  that  of  inactivity  appeared  in  the  women's  lists. 
The  boys  show,  on  the  average,  a  preference  for  words  denot- 
ing activity,  although  even  among  them  there  is  in  six  of  the 
twelve  grades  a  slight  predominance  of  words  denoting  pas- 
sivity. Among  the  girls  there  is  a  noticeable  preference  for 
words  denoting  passivity.     The  men  were  slightly  in  advance 


PREFERENCES  IN  BOYS  AND  GIRLS 


361 


$' 


[l 


IlL 


ii 
iii! 


VI     K     ? 


5^    S       t^ 


i!      i! 


hi 


i  ?  !i 


I       i! 


i!    I! 
il    iill 


ILp. 
HI 


Plate  E.     Choice  between  the  various  groups  of  words,  and  the  choice  between 
first  and  second  words  when  the  several  groups  were  offered.     (From  Table  V.) 

of  the  women  with  reference  to  food;  whereas  the  women 
exceeded  the  men  in  the  class  referring  to  wearing  apparel. 
In  this  experiment,  both  boys  and  girls  show  a  marked  prefer- 
ence for  words  denoting  food;  the  preference  is  stronger 
among  the  boys.  The  men  led  in  the  number  of  verbs 
written  and  the  women  in  the  number  of  adjectives.  Both 
boys  and  girls  show  a  great  preference  for  adjectives. 


362  M.  I.  STOCKTON 

The  larger  problem  concerning  the  difference  at  various 
ages  in  the  affective  life  of  boys  and  girls  may  be  considered 
in  two  aspects:  (i)  What  may  be  inferred  from  the  results  of 
this  experiment  concerning  the  problem?  (2)  How  are  such 
inferences  related  to  the  conclusions  of  other  investigators? 

Considering  now  the  first  of  these,  Plates  A  to  D  suggest 
a  tendency  toward  an  increase  of  preference  with  age.  That 
this  tendency  might  be  more  carefully  studied,  Table  VI.  was 
prepared.  This  table  shows  in  percentages  the  change  of 
preference  based  on  the  different  classes  of  ideas,  with  age, 
on  the  part  of  the  boys  and  the  girls.  Table  VII.  shows  the 
change  of  preference  based  on  the  position  of  the  words,  with 
age,  on  the  part  of  the  boys  and  the  girls.  Plate  F  gives  in 
graphic  form  the  data  of  Table  VI.;  and  Plate  G,  the  data 
of  Table  VII. 

Comparing  the  two  plates  (F  and  G),  one  sees  that  the 
preference  based  upon  the  position  of  the  words  is  more  pro- 
nounced than  the  preference  based  upon  ideas.  This  is 
certainly  contrary  to  the  expectations  of  the  writer  at  the 
beginning  of  the  experiments.  Although  one  is  not  surprised 
to  find  the  pupils  in  the  second  and  third  grades  showing  a 
preference  for  words  merely  according  to  their  position,  one 
does  not  look  for  such  purely  superficial  preference  in  the 
upper  grades.  One's  general  observation  that  children  grow 
more  thoughtful  after  nine  or  ten  years  of  age  is  upheld  by 
such  studies  as  Mrs.  Mary  Sheldon  Barnes'  and  Miss  Vos- 
trovsky's.  Mrs.  Barnes^  has  shown  that  the  ability  of  both 
boys  and  girls  to  make  legitimate  and  critical  inferences  from 
an  historical  incident  increases  after  eight  years  of  age.  The 
increase  at  first  is  gradual,  then  more  rapid.  Miss  Vostrov- 
sky2  found  an  increase  with  age  in  definite  answers  to  the 
question,  "Why  did  you  select  your  last  book?"  She  also 
found  an  increase  of  disbelief  in  superstitions  with  age.^ 

Comparing  Plates  F  and  G  more  closely,  one  sees  that 
among  the  girls  there  are  five  grades  in  which  the  curve  for 
preference  based  upon  ideas  rises  above  10  per  cent.;  in  four 

* 'Studies  in  Historical  Method,'  Boston,  1896,  p.  68. 

*  'Study  of  Children's  Superstitions,'  Barnes'  'Studies  in  Education,'  Vol.  I,  p.  123. 

''Children's  Reading  Tastes,'  Pedagogical  Seminary,  Vol.  6,  p.  523. 


PREFERENCES  JN  BOYS  AND  GIRLS 


363 


00 

tri 

N    t^  0\ 

HM 

N  1-1 

-0 

0 

<1 

■^vo  iJ^ 

uo  On  N 

0 

s 

w          w 

H 

n 

00  vq   r< 

0 

u 

vO 

<1 

\0    ^^ 

\0   c^   Th 

0 

OJ 

„ 

m 

C/2 

10  1-1  00 

>> 

^ 

T3 

0 

<1 

VO     CTi 

10  m  -ch 

ni 

T) 

C 

w 

n 

N    N    l^ 

*"■ 

1/1  M 

OJ 

u 

Cj 

^^■^ 

C/3 

u. 

0 

«t< 

00  00    c<^ 

OJ 

0  ^^  t^ 

C 

a; 

^ 

CJ 

pq 

Tj-^  OS 

a. 

VO   00  ■* 

c« 

0 

;-• 

<U 

j:3 

;s 

<j 

^l^ 

to" 

►H  vO  00 

C 

0 

a. 

dj 

c/i 

u 

|x! 

\0         c^ 

c^  >-<   0 

0 

% 

■M 

•      -13 

_G 

CJ 

^ 

V 

'0 

m 
0 

e 
0 

u 

'So 

-a 
c 

OS 

<n    ui    "> 

>.-r  >. 

o--  0 

p: 

IC 

m 

fu 


"^ 


Pi 


eu 


ovtJ-vo 

00   r^ 

d  c>d 

Ph, 
06  ci  i^ 


PhPh, 
00  -"^  ►-< 


Ph^Ph, 
TJ-CO  vO 


Ph^ 
00      _    On 
«  06    4- 


Ph^ 

N  vq 

'4'  rn  m 


Pi 

\0  00  cj 


o  •-  o 
pqOP3 


^ 


M  00    iri 

r^  tri  <> 


00   r» 
t^OO 


vq  00 
«^  06 


M  ^00 
\d  i-<  00 


00      Tj-    l-< 


t^  1-^  1-^ 


Tj-  -^  ON 


Q 


■^     s 


00  00   c<-i 


0--   o 

P5e3p5 


uriOO 

M    "H    11 

00    ON 

>/iO  b- 

"* 

■^^  •* 

00   0   OS 

1-1      M      HI 

NO^O    11 

l-^  N    1/1 

«    «    1-1 

•         VO 

'T^ 

(U 

> 

u 

MD  00    N- 

•  ^^ 

00   r<   0 

'O 

1-1   N   c) 

T^ 

!-• 

0 

'   ' 

^  ^  '^ 

1^ 

in  1/1 1-0 

ni 

W      «      1-. 

■u 

C) 

-1 

N    t/100 

N    ON  "1 

0 

A 

0 

0 

m:>  i-  . 

^ 

2  -- 

Ui 

U. 

4) 

Cl  ^    On 

J3 

0   »^  c^ 

H 

C»           NO 

H-     0     0 

l-l      HH      M 

00     ON 

OnnO   N 

■      -^3 

«j 

c 

xs 

S 

0 

V 

.^ 

M 

-a 

c 

ni 

>^-t:  t>. 

0--   0 

PC 

je 

Jeq  1 

o  o 
,    > 

2^ 


r^  O  ^J    o 


i-n 

Tj-  On 

M 

!->.  ON 

HH 

iri  d 

l^ 

r<l  0 

t^ 

w     ^ 

<M 

m  t^ 

MD 

ThUI 

0  00    Tj- 

M        11 

1/1 

1-  00 

ro  -^-00 

HH 

On  i/l 

« 

M     H 

-j-LT)   ^ 

On  "1  t^ 

■*  moo 

■>:>•  fOOO 

1-1  vo   ^^ 

d  d  d 


N  NO 
NO    On  t-^ 


U1NO  NO 
NO  NO  NO 


T»1  M     t~~ 
■4-  On  NO 


<o   03   w 

0--   o 
P5  0P5 


o  O 


a. 

t-. 

U. 

_; 

rt 

1/1 

<l) 

rt 

;s 

T) 

ff) 

C 

Tt 

t-H 

CO 

^ 

<u 

a 

*"" 

c 

'n 

8 

•t-i    ns 


0 

r» 

<D 

CJ 

^ 

n 

^ 

>. 

«s 

n 

u 

n 

X) 

■t-) 

«j 

-C 

13 

CO 

•n 

§ 

^ 

ii 

1"1 

rt 

■n 

u 

to 

CJ 

c«  -O 

is 

H 

4J 

Fi 

s 

«*-. 

■♦-» 

0 

3^4 


M.  I.  STOCKTON 


^.^BOYS 


C/fi^ 


Plate  F.  Varying  degree  of  preference  arising  from  difference  of  the  ideas 
conveyed  by  the  words  offered.  The  ordinates  indicate  the  relative  strength  of  such 
preference;  the  abscissae,  the  school-grades.     (From  Table  VI.) 


PREFERENCES  IN  BOYS  AND  GIRLS 


3«5 


> 


I— I      is      ^ 


H    ^ 


w 

H-l 

Ph 

OT 

m 

d. 

Ti 

^1 

<! 

O 

o 

S: 

— 1 

U 

!S 

iC 

O 

8 

12 

w 

K 

.^ 

H 

u 

b5     J- 

2: 


N  vo 

■+ 

00 

N  ^O    O 

N  11  11 

n 

00         o 

N    n    n 

www 

M  VO 

•al 

O^    f< 

w    w 

00    O    u-i 

pq 

00   r<   u^ 

^  M 

<) 

c<  00 

\0   w   OS 

w    c)    w 

C5 

•^^O   «J^ 

w   m  N 

^^^ 

r» 

-Jj 

VO   c»   Ov 

c<^        w 

^_^ 

c< 

PQ 

t^  O   -+ 

M    M    M 

\0  00    M 

<J 

ONTj-t^ 

00    -^VO 

n 

vovo  so 

00  00  00 

<j 

w    N    N 

^„^ 

M 

w 

M  VO    O 

CO  C)    t^ 

« 

-a 
<u 
c 
IS 

4J 

s 

•O 

o 

« 

u 

O 

'Si) 

c 

M     </5     CO 

>.-n  >- 

PC 

le 

)pql 

^ 


M 

c» 

N 

m  m  r*i 

M   N   M 

00  OO   r<-> 

M   OssO 

M           w 

iri 

M  m  «^ 

MD  Th 

O^SO    CO 

w   -^i-  CO 

,_^ 

o 

vo   •* 

r^  rl- w 

w           w 

^ ^ 

M 

O  \0  OO 

«o         CO 

^_.^ 

CI 

00    ■* 

C^    C»    N 

^ ^ 

o 

00    •* 

00    N    m 

M           w 

00           O 

IT)  N    CO 

\o  ■* 

00   co>>0 

VO   CO 

c<   O^O 

w   d   w 

^.^ 

c< 

N    w 

CO  cooo 

^ 

TJ 

1) 

c 

-Q 

a 

C5 

U 

,co 

t* 

-n 

c 

CJ 

CO      CO     CO 

x-c  >. 

O  ■-    O 

PC 

5U 

3pq 

Q 


00  vo 

r-. 

oo  c<   O 

N    w    M 

,^ 

N 

00    O 

VO  ^.t~- 

00    N    uo 

On  w  U-) 

VO         00 

c»  iri  CO 

d  -^  CO 

vo         CO 

OS  "-o  M 

C»     CO  CO 

N    ■*  CO 

OS  OS  Ti- 

w         w 

__^ 

c< 

M  N  t^ 

coO^ 

w 

ThTj-T*. 

00  N  O 

w           w 

c<  vo   OS 

SO   CO  OS 

c^        M3 

00  w   -^ 

00  00    CO 

CO  -^  On 

wow 

,_^ 

c< 

N  00 

l> 

--* 

c 
IS 
S 

8 

'5b 
-a 
c 

OS 

CO     CO    to 

>^-t:  >- 

o-=i  O 

PC 

5C 

3m  1 

-^ 


^ 


VO  00    N 

w   ^i-  CO 


-+SO 

iri 

CO 

■"" 

N 

o 

CO 

CO 

CO 

■^ 

" 

" 

CO  sq  N 

CO  r»  00 


vp 

00 

so 

HH 

00 

CO 

N 

d 

SO  00 

1/1 

(S 

ro 

M 

Tj- 

CO 

^,,^ 

M 

SO  00 

N 

CO 

t-> 

" 

CO      CO      CO 

o.l=  o 
PClOP5 


lO  tv.  w 
CO  d    c< 


OS  t^  CO 

c<  1^  d 


CJ    (--. 

dvsd  00 


so   w   C> 


so  lo^ 

lo  ds  t~» 


OO  00    CO 

00  lo  r>. 


so  --i- 

t^d  ^ 


CO  cooo 

-<i-dssd 


o-t:  o 
pqOPQ 


366 


M.  I.  STOCKTON 


♦«  — 


3<7  . 


no 


iO 


Boys 


I  of 


CIRL8 


%        Ai        BS       Af       af      A*^      Be      A6       B€      A7       B7       8 
Plate  G.     Varying  degree  of  preference  arising  from  mere  position  of  the  word 
in  its  pair.    The  ordinates  indicate  the  relative  strength  of  such  preference;  the  ab- 
scissa, the  school-grades.     (From  Table  VII). 


PREFERENCES  IN  BOYS  AND  GIRLS  3^7 

of  these  grades  the  curve  for  preference  based  upon  the  order 
of  words  is  below  lo  per  cent.  There  are  six  grades,  in  which 
the  curve  for  preference  based  upon  the  order  of  words  is 
above  lo  per  cent.;  in  five  of  these  grades  the  preference 
based  upon  ideas  is  below  lo  per  cent.  Among  the  boys, 
there  are  six  grades  in  which  the  curve  for  preference  based 
upon  ideas  rises  above  lo  per  cent.;  in  four  of  these  grades,  the 
curve  for  preference  based  upon  the  order  of  the  words  rises 
above  lo  per  cent.  There  are  eight  grades  in  which  the  curve 
for  preference  based  upon  the  order  of  the  words  rises  above 
lo  per  cent.;  in  five  of  these  grades,  the  curve  for  preference 
based  upon  ideas  rises  above  ten  per  cent. 

Table  VIII 

Showing  the  Degree  of  Intensity  of  Preference,  in  per  cent.  Computed  from 
Table  V  which  Shows  the  Average  Preference  for  the  Twelve  Grades 
Time  and  space  words. 

boys    7.8  in  favor  of  time. 

girls     5.6  in  favor  of  time. 
Words  denoting  activity  and  passivity. 

boys    2.2  in  favor  of  activity. 

girls     1.8  in  favor  of  passivity. 
Words  relating  to  dress  and  to  food. 

boys  16.2  in  favor  of  food. 

girls     9.2  in  favor  of  food. 
Verbs  and  adjectives. 

boys  12.6  in  favor  of  adjectives. 

girls  15.    in  favor  of  adjectives. 
•    Average  preference  for  first  words  in  all  classes  of  words. 

boys  12.2  in  favor  of  first  words. 

girls  12.05  ^n  favor  of  first  words. 

With  the  double  check  in  the  arrangement  of  the  words, 
described  on  page  348,  one  would  expect  that  where  the 
preference  for  first  words  is  pronounced,  there  would  be  a 
diminished  preference  for  either  class  of  ideas,  and  vice  versa. 
And  yet,  to  show  that  the  preference  for  first  words  may  be 
most  apparent  in  connection  with  a  preference  for  the  idea 
conveyed  by  the  word,  a  copy  of  two  lists  of  words  with  actual 
elections  is  submitted.  The  A  sixth  grade  boys'  lists  for  words 
relating  to  dress  and  food  are  selected  because  Table  III 
shows  a  marked  preference  for  words  relating  to  food  and 
also  for  first  words. 


368 


M.  I.  STOCKTON 


As  was  stated  previously,  these  two  sets  were  written 
some  five  weeks  apart.  The  number  after  each  word  Indicates 
the  number  of  boys  who  wrote  that  word.  First  words  are 
selected  215  times  in  the  *  second  set';  of  these,  125  relate 
to  food,  90  relate  to  dress.  In  the  'fourth  set,'  first  words  are 
selected  238  times;  of  these,  157  relate  to  food,  81  relate  to 
dress. 

Table  B 


A-SixTH  Grade: 

Boys'  Elections  of 

Words  Relating  to  Dress 

AND  Food 

Second  Set 

Fourth  Set 

Second  Set 

Fourth  Set 

dress 

13 

grapes 

16 

collar 

8 

cheese      15 

grapes 

4 

dress 

2 

cheese 

9 

collar         3 

nut 

12 

cap 

II 

banana 

12 

ribbon       6 

cap 

S 

nut 

7 

ribbon 

5 

banana     12 

hat 

II 

pie 

14 

velvet 

7 

apple        17 

pie 

6 

hat 

4 

apple 

10 

velvet        I 

berries 

12 

gloves 

10 

supper 

14 

cloak         6 

gloves 

5 

berries 

8 

cloak 

3 

supper     12 

coat 

II 

cake 

16 

silk 

9 

food          14 

cake 

6 

coat 

2 

food 

8 

silk             4 

bread 

12 

skirt 

9 

beef 

12 

lace            7 

skirt 

S 

bread 

9 

iace 

5 

beef          11 

vest 

8 

meat 

16 

tailor 

9 

turkey     17 

meat 

9 

vest 

2 

turkey 

8 

tailor          I 

fruit 

II 

shoes 

9 

pudding  14 

necktie      8 

shoes 

S 

fruit 

9 

necktie 

3 

pudding  10 

stockings 

8 

potato 

IS 

button 

7 

carrot       17 

potato 

9 

stockings 

3 

carrot 

10 

button       I 

butter 

12 

woolen 

9 

dinner 

14 

shawl         6 

woolen 

5 

butter 

9 

shawl 

3 

dinner      12 

Since  other  tabulations  show  the  same  results  as  the  one 
submitted,  one  may  conclude  that  the  first  word  was  given 
the  greater  preference  when  it  contained  the  more  attractive 
Idea;  when  the  more  attractive  idea  was  second,  the  preference 
for  the  first  word  either  was  much  reduced  or  disappeared 
entirely.  Although  with  the  majority  of  pupils  it  would  ap- 
pear that  the  two  different  kinds  of  preference — the  one  based 
on  idea,  the  other  based  on  mere  order  of  presentation — tended 
now  to  reinforce  and  now  to  offset  each  other,  yet  with  certain 
individuals  this  is  not  true;  they  let  themselves  be  influenced 
solely  by  position,  writing  the  first  word  (or  the  second  word) 
of  the  entire  list  of  twenty  words.     Indeed,  several  wrote  the 


PREFERENCES  IN  BOYS  AND  GIRLS 


369 


first  (or  second)  word  of  more  than  one  list.  The  following 
tabulation  throws  some  light  on  the  influence  of  this  factor 
in  the  different  grades. 

Table  C 

Showing  Selection  of  Words  According  to  Position  Exclusively 


Second  Grade. 

First  word .  . 

Second  word 
A  Third  Grade.  . 

First  word .  . 
B  Third  Grade.  . 

First  word .  . 

Second  word 
A  Fourth  Grade. 

First  word .  . 

Second  word 
B  Fourth  Grade. 

First  word .  . 

Second  word , 
A  Fifth  Grade. 

First  word .  . 

Second  word . 
B  Fifth  Grade. 

First  word .  . 
A  Sixth  Grade. 

First  word .  . 

Second  word . 
B  Sixth  Grade. 

First  word .  . 

Second  word. 
A  Seventh  Grade. 

First  word .  . 
B  Seventh  Grade. 

First  word .  . 
Eighth  Grade. 

First  word.  . 

Second  word . 

Total 


Girls 


S  girls 
S  girls 


16  lists 
8  lists 


7  girls         9  lists 


I  girl 
I  girl 

I  girl 
I  girl 


1  list 

2  lists 

I  list 
I  list 


1  girl  I  list 

2  girls  2  lists 

I  girl  2  lists 

7  girls  10  lists 

S  girls  8  lists 

4  girls  13  lists 

I  girl  2  lists 

3  girls  6  lists 


6  girls 
3  girls 


12  lists 
8  lists 


54  girls      102  Hsts 


Table  C  attracts  one's  attention  to  three  points: 
I.  The  influence  of  the  factor  of  the  position  of  the  word  is 
more  frequent  in  the  lowest  two  grades,  as  is  to  be  expected. 
The  excessive  breaking  out  in  the  A  sixth  grade  is  puzzling; 
yet  among  the  girls,  the  preference  for  the  first  word  and  for 
the  second  word  tend  to  balance.  In  the  eighth  grade,  one 
might  suspect  a  conspiracy  among  the  girls,  since  nine  out  of 
ten  girls  are  influenced  by  the  order  of  presentation.  How- 
ever, it  seems  improbable  that  any  plan  of  writing  the  words 


370  M.  I.  STOCKTON 

could  have  been  prearranged,  as  the  pupils  did  not  know  when 
the  words  were  to  be  presented.  In  fact,  they  were  rather 
led  to  think  that  each  presentation  was  the  last. 

2.  Table  C  shows  that  a  certain  order  was  followed  in 
one  hundred  and  two  lists  among  the  girls  and  in  seventy-nine 
lists  among  the  boys — giving  this  factor  a  greater  frequency 
among  the  girls  in  the  ratio  of  lo  to  8.  This  frequency  among 
the  girls  is  still  more  pronounced,  even  when  one  allows  for 
the  greater  number  of  girls'  papers.  There  were  648  girls' 
lists  of  twenty  words  and  600  boys'  lists  of  twenty  words — 
or  a  ratio  of  about  16  to  15. 

3.  This  tabulation  runs  parallel  at  certain  points  with  the 
general  preference  based  on  the  position  of  the  words  shown 
in  Table  VII.  In  Table  C,  in  the  second  grade,  the  prefer- 
ences for  the  first  word  and  for  the  second  word  are  almost 
balanced  among  boys  and  girls.  In  Table  VII.  there  is  a 
comparatively  small  percentage  of  preference  for  the  position 
of  the  word  shown  in  this  grade.  In  the  A  and  B  fifth  grades, 
Table  C  shows  little  influence  of  this  factor  of  the  position 
of  the  word;  in  Table  VII.  the  percentage  of  preference  is  low. 
In  the  A  sixth  grade,  one  would  expect  the  preference  for  the 
first  word  to  more  or  less  balance  the  preference  for  the 
second  word  among  the  girls  (Table  C).  But  Table  VII. 
shows  a  marked  preference  for  first  words.  However,  among 
the  boys  in  that  grade  the  two  tables  are  parallel.  The  girls 
of  the  eighth  grade  are  greatly  influenced  by  this  factor  of 
the  position  of  the  words  (Table  C),  and  there  is  also  a  marked 
preference  shown  in  Table  VII.  Yet  Table  VII.  gives  a  high 
percentage  of  preference  for  the  position  of  a  word  for  the 
boys  of  the  eighth  grade  while  Table  C  shows  almost  no 
influence  of  this  factor.  However,  the  small  number  of  boys 
in  this  grade  must  be  considered. 

With  reference  to  the  first  aspect  of  the  larger  problem; 
namely,  what  inferences  may  be  drawn  from  this  experiment 
concerning  the  differences  in  the  affective  life  of  boys  and 
girls  of  various  ages,  the  results  warrant  the  statement  that 
there  is  with  age,  a  general,  though  very  irregular,  increase 
in   the   preference   shown   for  the   various   classes   of  ideas. 


PREFERENCES  IN  BOYS  AND  GIRLS 


371 


Furthermore,  the  preference  Is  more  marked  among  the  boys 
than  among  the  girls.  The  irregularities  of  the  curves  of 
Plate  F  may  be  due  to  several  reasons.  At  least  eight  nation- 
alities are  represented  in  these  children,  and  In  some  of  the 
homes  the  parents  do  not  speak  English.  And  with  a  greater 
number  of  children  the  curve  would  tend  to  be  more  regular; 
150  boys  and  162  girls  are  the  basis  for  these  curves. 

It  is  also  noticeable  that  In  some  of  the  grades  the  children 
are  over  age.     Ayers^  gives  the  following  as  the  normal  age: 

Grade 2  3  4  5  6  7  8 

Age 7-9        8-10        9-11         10-12         11-13         12-14        13-IS 

The  following  (to  repeat  from  Table  A,  p.  348)  are  the 
average  ages  of  the  pupils  In  the  present  experiment: 


Grade 

2 

A3 

B3 

A4 

B4 

A5 

Age  of  boys 

Age  of  girls 

9-3 

8.6 

lO.I 

9-3 

10.9 

9-3 

10.9 
II. 

12.4 
II.7 

II-3 
12. 1 

Grade 

Bs 

A6 

B6 

A7 

B7 

8 

Age  of  boys 

Age  of  girls 

13-9 
12. 1 

13-3 
12.9 

13-6 
14. 

13-6 
12.9 

14.5 
14. 

14.8 

The  table  for  the  normal  age  Is  given  for  the  grade;  i.  e., 
for  the  sixth  grade,  the  normal  age  is  from  il  to  13.  Any 
pupil  in  the  sixth  grade  who  is  over  13  years  of  age  is  beyond 
the  normal  age.  Or,  any  pupil  In  the  A  sixth  grade  who  is 
over  12  years  of  age  Is  beyond  the  normal  age.  Glancing  at 
Table  A,  one  finds  that  the  boys  in  the  B3,  B4,  B5,  A6,  B6 
and  By  grades  are  beyond  the  normal  age;  the  girls  in  the  A3, 
A4,  B4,  A5,  A6  and  B6  grades  are  beyond  the  normal  age. 

After  studying  the  irregularities  in  the  curves  In  Plate  F, 
one  finds  that  In  the  grades  In  which  the  drops  occur  the 
pupils  are  over  age.  In  the  boys'  curve,  the  points  are  the 
B3,  B4  and  By  grades;  in  the  girls'  curve,  the  A3,  A5  and  A6 
grades.  Yet,  the  boys  of  the  B5,  A6  and  B6  grades  are  also 
above  the  normal  age  and  at  these  points  the  curve  is  steadily 
rising.  The  girls  of  the  A4  and  B6  grades  are  also  above  the 
normal  age  and  the  curve  Is  rising  at  these  points.  In  the 
B4  grade,  in  which  the  girls  are  beyond  the  normal  age, 
their  curve  has  reached  one  of  the  peaks. 

1  'Laggards  in  Our  Schools,'  1909,  p.  38. 


372  M.  I.  STOCKTON 

Considering  the  second  aspect  of  the  larger  problem,  these 
curves  would  have  been  more  comparable  with  the  curves  of 
other  studies  if  the  age  of  the  pupils  instead  of  the  grades  had 
been  used  as  the  basis  for  the  curves.  However,  some  rough 
comparisons  may  be  of  interest.  In  a  'Study  of  Children's 
Reading  Tastes'  by  Miss  Vostrovsky,^  curves  are  given  which 
show  the  increase,  with  age,  in  definiteness  of  answer  to  the 
question  "Why  did  you  select  your  last  book.?"  The  curves 
show  that  the  boys  increase  gradually  in  definiteness  with  no 
drops,  whereas  the  girls'  increase  is  not  so  great  nor  so  steady. 
There  are  two  drops  in  the  girls'  curve — at  ten  and  at  fifteen 
years  of  age — and  a  sudden  rise  from  fourteen  to  fifteen. 
She  infers  from  the  results  that  boys  are  more  independent 
in  their  selection  of  books  than  are  girls. 

In  a  'Study  of  Children's  Superstitions '^  by  the  same 
writer,  a  growth  in  the  critical  spirit  as  children  become  older 
is  shown.  The  curves  showing  the  number  of  superstitions 
described  as  untrue  by  boys  and  by  girls  display  the  same 
differences  between  boys  and  girls  as  was  mentioned  in  her 
other  study.  About  the  same  general  difference  between  boys 
and  girls  is  shown  in  Plate  F  as  was  shown  in  Miss  Vos- 
trovsky's  studies. 

In  Donaldson's^  showing  of  the  variation  in  brain  weight 
during  the  first  twenty-five  years,  the  curves  for  both  boys  and 
girls  are  far  more  regular  than  in  my  Plate  F,  and  yet  there 
are  some  points  of  similarity.  From  eleven  to  thirteen  years 
of  age,  the  boys'  curves  show  a  steady  rise  both  in  the  prefer- 
ences here  studied  and  also  in  brain  weight;  then  a  drop  in 
both  to  fourteen  and  then  a  rise  in  both  to  fifteen.  Among  the 
girls,  there  is  a  decided  rise  in  both  from  thirteen  to  fourteen, 
then  a  drop  in  both.  Fourteen  years  is  the  highest  point  in 
both.  There  is  far  less  similarity  between  these  curves  of 
Plate  F  and  the  two  curves  which  Donaldson*  gives  of  the 
changes  (A)  in  the  length  of  the  head  and  (B)  in  the  breadth 
of  the  head. 

^Pedagogical  Seminary,  Vol.  6,  p.  523. 

2  In  Barnes'  'Studies  in  Education,'  Vol.  I,  p.  123. 

''Growth  of  the  Brain,'  1895,  p.  105. 

< 'Growth  of  the  Brain,'  1895,  p.  112. 


PREFERENCES  IN  BOYS  AND  GIRLS  373 

Important  curves  for  comparison  are  those  given  by  Burk 
in  a  study  on  the  'Growth  of  Children  in  Height  and  Weight.'^ 
Two  of  these  sets  of  curves  give  the  annual  percentage  of 
increase  In  weight  (I.  J.)  and  the  annual  percentage  of  increase 
in  height  (K.  L.)  of  the  average  American  girl  and  boy. 
There  are  several  points  of  similarity  between  his  curves  I.  J. 
and  my  own  F.  The  girls'  curves  drop  from  eight  to  nine 
years  in  both;  and  twelve  years,  the  highest  point  in  I.  J., 
is  one  of  the  three  peaks  in  F.  However,  there  is  a  steady 
rise  from  nine  to  twelve  in  I.  J,;  whereas  in  F.  there  is  a  drop 
and  then  a  rise  before  twelve  years  is  reached.  The  boys' 
curves  I.  J.  and  K.  L.  are  similar  from  nine  to  fifteen  years. 
There  is  a  drop  from  ten  to  eleven  in  these,  comparable  \o 
that  from  A3  (10  yrs.)  to  B3  (11  yrs.)  In  F.  But,  in  the 
curves  I.  J.  and  K.  L.,  there  is  a  steady  rise  from  eleven  to 
fifteen,  the  highest  point;  whereas  in  F,  there  is  a  drop  from 
A4  (11  yrs.)  toB4  (12  yrs.)  followed  by  a  rise  to  A7  (13.6  yrs.), 
the  highest  point;  then  another  drop  and  another  rise. 

It  is  thus  probable  that  there  is  some  connection  between 
general  physical  and  mental  growth  and  the  development  of 
the  affective  life,  of  which  preference  Is  an  aspect. 

^  The  American  Journal  of  Psychology,  Vol.  9  (1897-98),  p.  263. 


:^-^;\ 


14  DAY  USE 

RETURN  TO  DESKi 

i:l/uv.hii 

LIBRARY 

This  book  is  due  on  the  last  date  stamped  below,  or 

on  the  date  to  which  renewed. 

Renewed  books  are  subject  to  immediate  recall. 


7  DAY  USE 


fUrnr'f^ 


JAN  1  0  1966 


p    'iMD-rABM 


WIOREC'D  -4  puj 


DURING 


SESSiONS 


LD  21-50m-12,'61 
(C4796sl0)476 


General  Library 

University  of  California 

Berkeley 


'>-y 


^^'i.*, 

/^ 


I 


■-'■J  '^i"  ^yy '* 


Km\< 


r^'^^^ 


